op chem 2 Flashcards

Question

25.What are the main components of Brass alloy? (A) Copper and Zinc (B) Copper and Strontium (C) Copper, Zinc and Nickel (D) Copper and Nickel

Answer 1

(A) (SSC CGL 2017) Exp: Brass is an alloy of Copper & Zinc. Cu = 60% & Zn = 40%. It is used for making plumbing & electric appliances.

Answer 2

(C) (SSC CGL 2017) Exp: Siderite (FeCO3) = Ore of Iron Galena (PbS) = Ore of lead Dolomite (CaCO3.MgCO3) = Ore of Magnesium & Calcium Epsom salt (MgSO4.7H2O) = Salt of Magnesium

Answer 3

(B) (SSC CGL 2017) Exp: Bronze is an alloy of copper & tin. It consists 88% of copper & 12% of tin. It is used for manufacturing the doors, windows, sculptures & utensils.

Answer 4

(B) (SSC CGL 2017) Exp: Stainless steel is made by mixing iron with carbon & metals like chromium, nickel & manganese. It is a corrosion resistant alloy which is used for making utensils

Answer 5

(A) [SSC CHSL 2010] Exp: In the given metals, Gold is nontoxic in nature while cadmium, cobalt and chromium are toxic.

Answer 6

(D) [SSC CHSL Exam, 2015] Exp: Sodium hypochlorite (NaOCl) when dissolved in water is commonly known as bleach or liquid bleach. It is used as disinfectant or a bleaching agent.

Answer 7

(A) [SSC CHSL 2012] Exp: Caustic soda is chemically known as sodium hydroxide (NaOH). It is deliquescent. Deliquescene: The property of certain compounds of taking up the moisture present in atmosphere and becoming wet when exposed is knwon as deliquescene. These compounds are known as deliquescent. eg. KOH, anhy.CaCl2, anhy. MgCl2, anhy.FeCl3.

Answer 8

(C) [SSC FCI 2012] Exp: Aluminium Powder is used in welding broken pieces of iron rail and machine parts.

Answer 9

(D) [SSC Steno 2014] Exp: Hydrogen Sulphide is a colourless gas with rotten egg smell.

Answer 10

(C) [SSC Tax Asst. 2009, FCI 2012] or Head of safety Matches contains - (A) P2O3 (B) Sb2S3 (C) Yellow Phosphorous (D) Red Phosphorous (D) [SSC MTS 2014] Exp: Tip of match stick contains red phosphorous.

Answer 11

(B) [SSC CGL 2002] Exp: Tip of match stick contains red phosphorous. Red phosphorous is an allotrope of phosphorous.

Answer 12

(D) [SSC CGL 2014] Exp: Most abundant inert gas in the atmosphere is Argon. Total percentage of noble gases in dry air is about 1% by volume, of which Argon (0.93%) is the major component.

Answer 13

(C) [SSC CGL Exam, 2015] Exp: In fireworks, Green colour is displayed due to chloride salts of Barium. Salts used for different colours are:- Salt Colour 1. Strontium sulphate - Red 2. Strontium Carbonate - Bright Red Colour 3. Sodium Salt - Golden yellow 4. Copper Salt - Blue 5. Aluminium Powder - Silver Colour.

Answer 14

(B) [SSC CHSL 2014] Exp: For the Formation of salts, sodium will displace Hydrogen because in electrochemical series Hydrogen is below sodium. 2HCl + 2Na 2NaCl + H2

Answer 15

(D)Exp: Silver iodide, sodium chloride and dry ice are oftenly used fluid chemical for artificial rain or cloud seeding.

Answer 16

(D) [SSC CHSL 2014] Exp: Neon (noble gas) is used in beacon light as safety signal for air navigators because its light has fog penetrating power.

Answer 17

(C) [SSC CGL 2014] Exp: Hydrogen was discovered by Henry Cavendish in 1766. Hydrogen is the lightest gas. It is known as fuel of future.

Answer 18

(A) [SSC FCI 2012] Exp: Hydrogen Gas is used in the production of vegetable ghee. This process is known as Hydrogenation.

Answer 19

(A) [SSC CPO 2009] Exp: Chemical formula of ozone is O3, so ozone contains only oxygen. Ozone is a pale blue gas.

Answer 20

(A) (SSC CHSL 2016) Exp: Chemical formula of ozone is O3, so ozone contains only oxygen. Ozone is a pale blue gas.

Answer 21

(B) (SSC CHSL 2012) Exp: Carbon dioxide turns lime water into calcium carbonate. ZnCO 3 ZnO+CO2 (Milky Appearance) yellow ZnO(white) Zinc Carbonate Cooling Ca(OH) + CO 2 2 CaCO + H O 3

Answer 22

(D) Exp: Noble gases are monoatomic so formation of He2 is not possible.

Answer 23

(B) [SSC CGL 2006, SSC CHSL 2010] Exp: Chemically Bleaching powder is known as calcium hypochlorite and its chemical formula is CaOCl2. It is used in disinfection of water and as a bleaching agent. It is also used for the manufacturing of chlorine gases and chloroform (CHCl3)

Answer 24

(A) Exp: Calcium hypochlorite (bleaching powder) is an inorganic compound with formula CaOCl2. It is used as dehydrating agent along with CaCl2.

Answer 25

(B) [SSC CHSL 2011] Exp: Marble is a metamorphic rock, which is the result of metamorphosis of Lime stone. Chalk is also a type of Lime Stone. Slaked Lime is a colourless crystal with chemical formula Ca(OH)2.

Answer 26

(A) [SSC CHSL 2011] Exp: Lime water becomes milky when exposed to air due to the presence of carbondioxide. Ca(OH)2 + CO2 CaCO3+ H2O

Answer 27

(C) (SSC CHSL 2015) Exp: Oxygen, Nitrogen and Hydrogen are colourless gases while chlorine is a greenish yellow coloured gas.

Answer 28

(A) (SSC CGL 2006) Exp: Chemically Lime water is known as calcium Hydroxide and its chemical formula is Ca(OH)2.

Answer 29

(A) (SSC Tax Asst. 2007) or Gas is used as a fire extinguisher is- (A) Neon (B) Nitrogen (C) Carbon dioxide (D) Carbon monoxide (C) (SSC CHSL 2013) Exp: Carbon dioxide Gas is used as a fire extinguisher. It stops the supply of oxygen which is necessary for the burning of object because CO2 is heavier than oxygen.

Answer 30

(B) (SSC Steno 2010) Exp: Mercury is liquid Metal, it is an essential constituent of Ama lgams. It is found is liquid state at room temperature.

Answer 31

(D) [SSC MTS 2008, SSC CGL 2012] Or

Answer 32

(D) (SSC MTS 2011, SSC CGL 2015) Exp: Dry ice is solid carbon dioxide (CO2) with a low temperature of -78° C (-109° F). At atmospheric pressure, solid CO2 sublimates directly to vapour without a liquid phase.

Answer 33

(D) (SSC CGL 2016) Exp: Since all the electrons are firmly held in C-C - bonds, there are no free electrons in a diamond crystal. Therefore, diamond is a bad conductor of electricity.

Answer 34

(D) [SSC CHSL 2012] Exp: Charcoal or coal of wood is a black Brownish Product which is formed when wood or bone is combusted in the absence of oxygen and water. Volatile constituents from animals and vegetation are removed. Charcoal is used as an adsorbent in water treatment because charcoal adsorbs the pollutants present in water.

Answer 35

(A) [SSC CGL 2008] Exp: At the lowest temperature Hydrogen turns into Liquid.

Answer 36

(C) [SSC CPO 2009] Exp: Heavy water means water containing maximum density. It contains Deuterium, an isotope of Hydrogen. It contains 11% more density than simple water but physically and chemically is same as simple water. It is used as a moderator in nuclear reactors.

Answer 37

(C) [SSC GD 2015] Exp: Heavy water is chemically deuterium oxide (D2O). Heavy water contains heavy hydrogen or deuterium.

Answer 38

(D) [SSC CGL 2014] Exp: Soda water contains Carbon dioxide (CO2) gas.

Answer 39

(B) [SSC CGL 2005] Exp: Phosphorous is used for making the smoke bombs. It is also used in making match box, crackers and explosive materials.

Answer 40

(A) Exp: Hydrogen peroxide is an effective sterilizing agent, when active oxygen disappears from it, then it forms water. 2H2O2 2H2O + O2

Answer 41

(C) [SSC MTS 2014] Exp: In deep sea water, divers used a mixture of oxygen, Nitrogen and Helium which is known as Trimix.

Answer 42

(D) [SSC CHSL 2015] Exp: Dissolved ammonia (NH3) in water makes it basic. Polar characteristics of ammonia and its tendency to form bonding shows its High Solubility in water. In aqueous Solution Ammonia act as a base and form Hydroxyl and Ammonium ion. NH3 + H2O NH4 + OH-

Answer 43

(C) [SSC Sec. Officer 2007] Exp: Magnesium is extracted from sea salts MgCl2.6H2

Answer 44

(B) [SSC CGL 2013] Exp: Silicon is a polymer of dialkyl dichloro silane (R2SiCl2). Silicones: These are organosilicon polymeric compounds containing Si-O-Si linkages. These have general formula of (R2SiO)n having (R2SiO-) as a repeating unit. (R may be alkyl or phenyl group). The starting material for the manufacturing of silicones is alkyl or aryl substituted chlorosilanes.

Answer 45

(C) [SSC MTS 2002, SSC CHSL 2011] Exp: Helium-oxygen mixture is used by deep sea divers in preference to nitrogen oxygen mixture because of its very low solubility in blood. It is also used to assist breathing in asthma.

Answer 46

(A) Exp: CO is a neutral oxide. Neutral oxides show neither basic nor acidic properties and hence do not form salt when reacted with acids or bases. eq. NO, N2O etc

Answer 47

(D) Exp: Metal oxide which show both acidic as well as basic behaviour are known as amphoteric oxide. These oxides react with acids as well as base to produce salt and water. eg: ZnO, SnO2, PbO2, Al2O3 etc

Answer 48

(B) [SSC MTS 2006] Exp: Sedimentary rocks are important sources of natural resources like coal, fossil fuels or ores. Depending upon the quantity of carbon% coal are of four type- 1. Peat coal Carbon content is 50 - 60%. It is lowest grade of coal. 2. Lignite coal Carbon content is 65 - 70%. It is known as brown coal 3. Bituminous coal Carbon content is 70-85%. It is also known as soft coal. 4. Anthracite coal Carbon content is 90% - 95%. It is the best grade of coal.

Answer 49

(D) [SSC CHSL Exam, 2014] Exp: In the given elements, Helium is an example of noble gas. Noble gases have completely filled orbitals (stable configuration). Helium, Neon, Argon, Krypton, Xenon and Radon are Noble gases.

Answer 50

(D) Exp: Haematite (Fe2O3) is not a form of carbon. It is an ore of Iron.

Answer 51

(A) [SSC Sec off. 2007] Exp: In Lead pencils, Lead is 0%. In lead pencils, graphite is used.

Answer 52

(A) [SSC CGL MST 2010, SSC Steno 2005, 2002] Exp: Graphite is used in pencils because of its ability to leave grey marks on paper. It is crystalline allotrope of carbon. Note: In lead pencils lead percentage is 0

Answer 53

(C) [SSC MTS 1966, SSC Tax Asst. 2006] Exp: Plaster of Paris is formed by the partial dehydration of Gypsum Salt. It is used in the medicals for plastering the bones, in making toys and statues etc. CaSO4. 2H2O 373 K (CaSO4). 1 2 H2O + 3 2 H2O (Gypsum) (POP)

Answer 54

(A) [SSC CHSL Exam, 2010] Exp: Fluorine is the most reactive among the Halogens. Fluorine has the lowest bond dissociation enthalpy. This is due to weak F-F bond because of the repulsion between the non-bonding electrons in the small molecule.

Answer 55

(A) [SSC CHSL Exam, 2013] Exp: Bromine is the only nonmetal which is found in liquid State at room temperature. It has reddish brown colour.

Answer 56

(A) [SSC MTS 2002, SSC Sec off. 2006] Exp: Silver Bromide is used to prepare the Light sensitive chemical (Emulsion) over photographic film, because these are soluble in Hypo solution (Sodium thiosulphate) which makes photographic film transparent.

Answer 57

(A) [SSC CHSL 2014] Exp: The chemical name of Hypo commonly used in photography is sodium thiosulphate (Na2S2O3).

Answer 58

(C) [SSC CGL 2010] Exp: Silver halides are used in photographic plates because they are Reduced by Light.

Answer 59

(A) [SSC CHSL Exam, 2012] Exp: Chemically Philosopher Wool is a zinc oxide (ZnO). It is also known as zinc white. It is a constituent of cigarette filters. It can be used in lotions and creams to protect skin from UV light.

Answer 60

(B) [SSC Steno 2014] Exp: Oxygen is a combustion nourishing gas. It is a supporter of combustion.

Answer 61

(D) [SSC CPO 2009] Exp: Carbon monoxide (CO) is an inflammable gas. Hydrogen is also an inflammable from the given options and oxygen is combustion supporting gas.

Answer 62

(C) [SSC MTS 2013] Exp: Carbon compounds are easily combustible in the presence of air and their melting point and boiling point are low. They are water insoluble and mainly consists of carbon & hydrogen.

Answer 63

(A) [SSC Sec officer 2007] Exp: Chemical name of common salt is sodium chloride and it's also known as Rock Salt. Its chemical formula is NaCl.

Answer 64

(C) [SSC CHSL Exam, 2015] Exp: Sodium chloride or Table salt occurs in nature as the mineral Halite.

Answer 65

(B)Exp: Sodium carbonate is commonly known as washing soda. It is manufactured by solvay-ammonia process. It is white crystalline solid which crystallizes as decahydrate (Na2CO3.10H2O).

Answer 66

(C) [SSC CHSL Exam, 2014] Exp: Chemical formula of washing soda is Na2CO3.10H2O.

Answer 67

(A) (SSC CHSL 2016) or Commercial name of sodium bicarbonate is - (A) Washing Soda (B) Baking Soda (C) Bleaching Powder (D) Soda Ash (B) [SSC MTS 2010, SSC Tax Asst. 2009] Exp: Commercial name of Sodium bicarbonate (NaHCO3) is Baking soda because on heating it decomposes to evolve bubbles of CO2 (leaving holes in cakes or pastries to make them light & fluffy).

Answer 68

(B) [SSC CHSL 2014] Exp: Chemical name of baking soda is Sodium bicarbonate (NaHCO3).

Answer 69

(C) (SSC CHSL 2016) Exp: Sodium bicarbonate (NaHCO3) is known as baking soda. It is used in fire extinguisher for generating CO2.

Answer 70

(A) [SSC Tax Asst. 2009] Exp: Slaked lime is used as building material in the form of mortar. It is prepared by mixing slaked lime with 3-4 times its weight of sand. The mixture is made into a thick paste with gradual addition of water. This paste is called mortar.

Answer 71

(C) [SSC CGL 2015] Exp: Most commonly bleaching agent is chlorine (Cl2). It bleaches only in presence of water. Since chlorine bleaches by oxidation, the bleaching action of chlorine is permanent. Chlorine produces HCl during bleaching therefore it is used only for paper pulp, wood pulp and cloth.

Answer 72

(C) [SSC CGL Exam, 2008] Exp: Because it is a noncombustible (non-flammable) gas.

Answer 73

(B) [SSC MTS Exam 1999] Exp: Helium gas is lighter than air and non-flammable (noncombustible) so it is used in balloons.

Answer 74

(C) [SSC CPO Exam, 2011] Exp: Because helium is less dense than air.

Answer 75

(B) [SSC Steno Exam, 2014] Exp: Helium gas is used in balloons, because it's lighter than air. Earlier it was used in tyres but now a days Nitrogen is filled in Aeroplane tyers.

Answer 76

(C) [SSC CHSL 2010, SSC Steno 2011] Exp: Xenon is a noble gas (Chemical element) with symbol Xe and atomic number 54. Due to Low Ionization Potential it can react with fluorine and oxygen in special conditions and forms chemical compounds. Such as XeF2, XeF4, XeOF4 etc.

Answer 77

(C) [SSC CHSL Exam, 2014] Exp: The maximum density of water is at 40C. Above this temperature, its density decreases because its volume increases. Below this temp its density also decreases.

Answer 78

(B)Exp: White Phosphorous is insoluble in water but soluble in benzene, carbon disulphide liquid NH3. It is stored under water to protect it from air. Its ignition temperature is very low and therefore, it catches fire in the air to form white dense fume.

Answer 79

(D) [SSC Stenographer 2005] Exp: Alkali metals (Li, Na, K etc) are placed under the kerosene oil because they can be easily oxidised with air and water due to their high reactivity.

Answer 80

(D) [SSC MTS 2014] Exp: Nitrous oxide (N2O) is commonly known as laughing gas or happy gas. It can be used as an anesthetic in surgery and dental treatment.

Answer 81

(D) [SSC CPO 2010] Exp: Normally Sand and sodium bicarbonate is used in dry Powder fire extinguisher.

Answer 82

(A) Exp: All electrons are paired in noble gases (inert gases) so no. of unpaired electrons in noble gases is zero.

Answer 83

(D) [SSC CGL 2011] Exp: Radon gas is used in treatment of cancer. It is radioactive in nature. It is the only noble gas that is not present in atmosphere. It is the heaviest gas at room temperature. It is obtained as a decay product of 88Ra226. 222 226 4 86 88 2 Ra Rn He

Answer 84

(B) Exp: Old oil painting becomes black due to formation of lead sulphide (PbS). When H2S gas (present in air) react with lead (present in lead paint) formation of lead sulphide takes place.

Answer 85

(A) Exp: After Hydrogen, Helium is the Second most abundant element on the surface of sun. Helium - 24.85% Iron - 0.16% Carbon - 0.29% Neon - 0.12%

Answer 86

(A) [SSC Steno Exam, 2005] Exp: Asbestos contains silicates of metals such as calcium magnesium, nickel, iron and manganese etc.

Answer 87

(A) (SSC CGL 2016) Exp: Mercury metal has melting point of -37.9ºF. This is due to weak metallic bonding as mercury has fulfilled valence orbitals. Melting point is the temperature at which a substance changes from solid to liquid state.

Answer 88

(B) [SSC CGL Exam, 2010] Exp: If the bullets could not be removed from gunshot injury of a man, it causes poisoning in the body due to the presence of Lead.

Answer 89

(C) [SSC CPO 2005, SSC MTS 1999] Exp: Purity of gold is measured in carat. 24 carat gold is pure gold% of pure gold in 18 carat gold can be found by following method 18 24 ×100 = 75%

Answer 90

(A) [SSC CPO 2007] Exp: Purity of gold is expressed in terms of carat. Purest form of gold is 24 carat.

Answer 91

(A) [SSC MTS 2002, SSC CHSL 2015] Exp: Gold is the most valuable metal, so it is known as king of metal.

Answer 92

(C) [SSC Sec off. 2006] Exp: Standard 18 carat Gold Sold in Market Contains 18 parts Gold and 6 Parts of Metal.

Answer 93

(D) [SSC CHSL Exam, 2011] Exp: Quality of coal depends upon the amount of carbon present in it. Due to the High temperature and pressure in earth cast peat coal (Less than 50% carbon) formed, then lignite coal (60-70% Carbon) formed, Bituminous coal (60-80% carbon) and then of Best quality of coal Anthracite (85-90% carbon). Lignite coal is also known as Brown coal.

Answer 94

(D) Exp: Depending upon the quantity of carbon% coal are of four type- 1. Peat coal Carbon content 50 - 60%. It is lowest grade of coal. 2. Lignite coal Carbon content 65 - 70%. It is known as brown coal 3. Bituminous coal Carbon content 70-85%. It is also known as soft coal. 4. Anthracite coal Carbon content 90% - 95%. It is the best grade of coal.

Answer 95

(D) [SSC CPO 2015] Exp: Boron behaves chemically both as Metal and a Non- Metal. It belongs to 13th group of periodic table.

Answer 96

(C) [SSC DEO 2008] Exp: Silver has maximum electrical conductivity and thermal conductivity order of conductivity is as follows: Silver > Copper > Aluminium > Lead.

Answer 97

(C) [SSC CPO 2007] Exp: Cause of illumination of metals is the reflection of light due to the presence of free electrons.

Answer 98

(C) [SSC CGL 2015] Exp: Heavy metals have higher densities as compare to lighter metals. Metals having densities greater than 5g/cm3 are categorized as heavy metals. For example Cadmium, Copper, Lead etc.

Answer 99

(B) [SSC MTS 2006] Exp: In metals Lead is the most bad conductor, while gold, Silver and Iron are good conductors.

Answer 100

(C) [SSC CHSL 2012] Exp: Aluminium is the metal which protects itself by the rusting with its own layer of oxide.

Answer 101

(B) [SSC CHSL Exam, 2015] Exp: From the given options, Only Gold and Copper are non-silver in colour. Gold is of Golden and Copper is of Reddish Brown Colour.

Answer 102

(B) [SSC CGL Exam, 2015] Exp: Cesium has least melting points from the given Metals and is easily ionized when exposed to Light. It is also used in Atomic Clocks.

Answer 103

(B) [SSC MTS 2008] Exp: Iron, Nickel and Cobalt are Magnetic Materials so these can be used as electromagnet but copper cannot be used as electromagnet.

Answer 104

(A) [SSC CGL 2006] Exp: Quartz is the crystalline form of silicon dioxide.

Answer 105

(B) [SSC CGL 2014] Exp: Graphite is used in the making of Pencils. It is an allotrope of carbon.

Answer 106

(A) [SSC CHSL 2012] Exp: In graphite, Layers are Held together by Vander walls forces. These are weak attractive forces between atoms or non-polar molecules. It is named after dutch scientist Johannes Diderik Van Vander Wall.

Answer 107

(C) [SSC CHSL 2012] Exp: Solid Lubricants are the substances in which the friction between two layers is reduced due to their solid State. Graphite, Tungsten disulphide, Molybdenum disulphide are important solid lubricants

Answer 108

(C) Exp: In diamond, 4 valence electrons of a carbon atom forms strong covalent bond and form tetrahedral structure due to sp3 hybridisation. Graphite is hexagonal layered structure and it is soft. Due to difference in crystalline structure diamond is harder than graphite.

Answer 109

(C) [SSC CHSL 2011] Exp: One carat of Diamond is equal to 200 mg.

Answer 110

(A) [SSC CHSL 2011] Exp: The solid material which breaks into small pieces on hammering are called brittle. The non-metals are generally brittle in nature.

Answer 111

(B) [SSC CHSL 2011] Exp: Fire-Fighting Cloths are made from Asbestos because it has heat resistant property.

Answer 112

(C) [SSC CHSL 2012] Exp: Fullerene is a newly discoverd crystalline carbon allotrope contains 60 C atoms. It was discovered by R.E. smalley and R.F. Curl and H.W. Kroto for this discovery these scientist shared the 1996 Noble Prize in chemistry. Fullerences (C60) are the only pure form of Carbon. It is also known as Buckminster fullerene or bucky ball.

Answer 113

(B) [SSC CHSL Exam, 2015] Exp: Chilesalt peter is the common name of sodium nitrate (NaNO3).

Answer 114

(B) (SSC CHSL 2016) Exp: Mercury is the only metal which exists in liquid state at room temperature. This is due to weak metallic bonding as in mercury as it has fulfilled valence orbitals.

Answer 115

(C) (SSC CHSL 2016) Exp: White phosphorus consists of P4 units. It glows in dark (property known as chemiluminiscence) due to its slow oxidation. It is most reactive allotrope of phosphorous.

Answer 116

(D)Exp: First Group of periodic table contains lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). These are called as alkalimetals since their hydroxies form strong bases or alikali. The first ionization enthalpies of the alkali metals are very low. So they easily lose electrons.

Answer 117

(A) (SSC CHSL 2016) Exp: Water has the maximum density.

Answer 118

(D) (SSC CHSL 2016) Exp: Nitrogen was discovered by Dainel Rutherford in 1772. In the molecular form, it exists as diatomic molecule (N2) having triple bond between two nitrogen atoms. Dinitrogen is chemically inert at room temperature.

Answer 119

(B) (SSC CHSL 2016) Exp: In the given options, Sulphur dioxide is toxic gas with a pungent and suffocation odour while ethane, hydrogen and carbon monoxide are odourless.

Answer 120

(C) (SSC CHSL 2016) Exp: Activated carbon is also called Activated charcoal due to its high degree of micro- porosity. It acts as an adsorbent.

Answer 121

(D) (SSC CHSL 2016) Exp: Macronutrients are nutrients that are required in larger amount by plants. eq: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous Potassium, Calcium, Sulphur, Magnesium.

Answer 122

(D) (SSC CHSL 2016) Exp: In the given options krypton is a gas. So krypton has the lowest melting point. Order of Melting Point:- Gas < liquid < solid.

Answer 123

(C) (SSC CHSL 2016) Exp: Conduction of electricity in metals is possible due to presence of free electrons.

Answer 124

(C) (SSC CHSL 2016) Exp: Water has maximum density (1 g cm-3) at 4ºC. This property is very useful for aquatic life. In severe cold, the upper layer of the sea water freezes. The heavier water has more density than that of ice is present below the surface of ice. The ice layer formed on the surface of a lake in winter does not sink to the bottom. Ice provides a thermal insulation for the water below it. The sea animals can live safely in water under these conditions.

Answer 125

(A) (SSC CHSL 2016) Exp: Bromine is a nonmetal so it has lowest melting point. Non-metals have low melting point compared to metals.

Answer 126

(C) (SSC CHSL 2016) Exp: Heavy water is D2O. (Deuterium oxide).

Answer 127

(D) (SSC CHSL 2016) Exp: Solid carbon dioxide is known as dry ice. Dry ice is also called Cardice. Dry ice shows sublimation. It is used for making cold baths, used as coolant for preserving perishable articles in food industry, for curing local burns and in hospitals for surgical operations.

Answer 128

(A) (SSC CHSL 2016) Exp: Oxygen was discovered by carl wilhelm scheele in 1772 and Joseph Priestley in 1774 but Priestley is given priority because his work was published first, but it is not given in options.

Answer 129

(A) (SSC CGL 2016) Exp: Nitrous oxide is known as laughing gas. Mixture of nitrous oxide and oxygen is used as anaesthetic.

Answer 130

(D) Exp: In the given options statement (D) is false. While (A), (B) and (C) are true. Radon is obtained from decay of radium. 226 222 4 Ra Rn + He 88 86 2 Helium is an inert gas due to stable configuration. Xenon is the most reactive among rare gases due to low ionisation enthalpy. The most abundant rare gas found in the atmosphere is Argon.

Answer 131

(A) (SSC CHSL 2016) Exp: Cadmium ion - Cd2+ Nitrate ion - NO3 - Chemical formula of cadmium nitrate is Cd (NO3) 2

Answer 132

(B) (SSC CHSL 2016) Exp: Common name of hydrogen peroxide is bleach (liquid) because H2O2 is used as bleaching agent for delicate materials like textiles (silk, wool) paper pulp, straw, leather, ivory, oils and fats.

Answer 133

(C) (SSC CHSL 2016) Exp: Radon has the lowest melting point due to weak vander waal force in noble gases. It is a non-metal. Noble gases have low melting point and boiling point compared to other elements.

Answer 134

(B) (SSC CHSL 2016) Exp: Barium loses 2 electrons to achieve noble gas electronic configuration.

Answer 135

(C) (SSC CHSL 2016) Exp: The common name of sodium tetraborate decahydrate is Borax (Na2B4O7.10H2O

Answer 136

(A) (SSC CHSL 2016) Exp: Ammonium ion - NH4 + Chromate ion - Cr2O7 -2 Chemical formula of Ammonium dichromate is (NH4) 2Cr2O7

Answer 137

(C) [SSC FCI 2012] Exp: Nitrous oxide gas is used as a mild anaesthetic in dental and other minor surgical operations when mixed with 10% O2.

Answer 138

(C) (SSC CHSL 2016) Exp: Noble gases have low melting point and boiling point compared to other elements. Argon is a noble gas

Answer 139

(D) (SSC CHSL 2016) Exp: The common name of sulphur is brimstone.

Answer 140

(C) (SSC CHSL 2016) Exp: Aluminium ion = Al3+ Chloride ion = Cl- Chemical formula of Ammonium Chloride = AlCl3

Answer 141

(A)Exp: Ammonium ion:- NH4 + Oxalate ion:- C2O4 2- Chemical formula of Ammonium oxalate is :- (NH4) 2 C2O4

Answer 142

(D) (SSC CHSL 2016) Exp: Chemical formula of water is H2O. 2 atoms of H and 1 atom of O combines to make 1 molecule of water.

Answer 143

(D) (SSC CHSL 2016) Exp: Ammonium ion - NH4 Sulphate ion - 2 SO4 - NH4 2 SO4 - (NH4) 2SO4 So the chemical formula of Ammonium sulphate will be (NH4) 2SO4

Answer 144

(D) (SSC CHSL 2016) Exp: In the given options krypton has the lowest melting point because it is a noble gas (inert gas). Noble gases have low melting point and boiling point compared to other elements.

Answer 145

(A) (SSC CHSL 2016) Exp: Common name of Magnesium Sulphate hepta hydrate is Epsom salt (MgSO4.7H2O).

Answer 146

(A) (SSC CHSL 2016) Exp: Helium is a noble gas (inert gas) so it has lowest melting point. Noble gases have low melting point and boiling point compared to other elements

Answer 147

(D) (SSC CHSL 2016) Exp: Chemical formula of ammonia is NH3. It is manufactured in Lab by Haber process.

Answer 148

(B) (SSC CHSL 2016) Exp: In 1985, a third crystalline allotrope of carbon called fullerene was discovered collectively by three scientists namely R.E. Smalley, R.F. curl and H.W. Kroto shared the 1996 Noble prize in chemistry.

Answer 149

(A) (SSC CHSL 2016) Exp: Halons are the gases which contains halogen atom as an essential element. It is used for fire suppression & refrigeration. Carbon tetra chloride, Iodomethane, and Bromomethane are Halon as they contain Halogen atom.

Answer 150

(B) (SSC CHSL 2016) Exp: In the given options, Hydrogen is a gase

Answer 151

(D) (SSC CHSL 2016) Exp: Ammonium ion = NH4 + Chloride ion = Cl- Chemical formula of Ammonium chloride - NH4Cl

Answer 152

(B) (SSC CHSL 2016) Exp: In the given options, Nitrogen is gaseous nonmetal so it has the lowest melting point. Iron and lead are metals while Iodine is solid nonmetal having higher melting point than the melting point of nitrogen.

Answer 153

(D) (SSC CHSL 2016) Exp: Filament of electric bulb is made of Tungsten metal. Tungsten metal has highest melting point (3,422ºC).

Answer 154

(D)Exp: Chemical formula of Ammonia - NH3 Phosphine - PH3 Nitrogen dioxide - NO2 Aluminium nitride - AlN

Answer 155

(A) (SSC CHSL 2016) Exp: In the given options, Oxyen is a gaseous nonmetal so it has the lowest melting point. Non- metals have low melting point compared to metals.

Answer 156

(B) (SSC CHSL 2016) Exp: Aluminium ion - Al+3 Nitride ion - N-3 So chemical formula of Aluminium nitride will be AlN.

Answer 157

(D) (SSC CHSL 2016) Exp: Baking soda is sodium bicarbonate. Its chemical formula is NaHCO3.

Answer 158

(B) (SSC CHSL 2016) Exp: In the given options, Hydrogen is gas so it has lowest melting point. Order of melting point:- Solid > liquid > gas.

Answer 159

(C) (SSC CHSL 2016) Exp: In the given options, Neon is noble gas so it has lowest melting point. Noble gases have low melting point and boiling point compared to other elements.

Answer 160

(B) (SSC CHSL 2016) Exp: Ammonium ion - NH4 Nitrate ion - NO3 - So chemical formula of ammonium nitrate will be NH4NO3.

Answer 161

(A) (SSC CHSL 2016) Exp: In the given options, Xenon is a noble gas (inert gas). So it has the lowest melting point. Noble gases have low melting point and boiling point compared to other elements.

Answer 162

(C) (SSC CHSL 2016) Exp: Argon is a noble gas (inert gas) so it has lowest melting point. Noble gases have low melting point and boiling point compared to other elements.

Answer 163

(A) (SSC CHSL 2016) Exp: In the given options, Oxygen is a nonmetal so it has lowest melting point. Non- metals have low melting point compared to metals.

Answer 164

(D) (SSC CHSL 2016) Exp: Washing soda is chemically known as sodium carbonate decahydrate (Na2CO3.10H2O).

Answer 165

(D) (SSC CHSL 2016) Exp: In the given options Fluorine is nonmetal so it has lowest melting point. Non- metals have low melting point compared to metals. Sulphur has higher melting point compared to fluorine.

Answer 166

(D) (SSC CHSL 2016) Exp: Hydrogen has three isotopes. These are called - (i) Protium or ordinary hyrdogen [1 1H]- it is most abundant isotope of hydrogen.(ii) Deuterium or heavy hydrogen [2 1H or D]. (iii) Tritium [3 1Hor T] :- It is the least abundant of all isotopes of hydrogen. Atomic properties of isotopes of Hydrogen. Property H D T Relative(%) 99.985 0.0156 10-15 Abundance Relative Atomic 1.007825 2.014102 3.016049 Mass(gmol-1)

Answer 167

(B) (SSC CGL 2016) Exp: Hydrated sodium aluminium silicates, (Na2Al2Si2O8.xH2O) is known as Zeolite. It has property of exchanging Ca+2 and Mg+2 ions present in hard water with sodium present in it. Zeolite can be represented by the general formula Na2Z where Z = Al2Si2O8. xH2O.

Answer 168

(D) (SSC CGL 2016) Exp: Helium-Oxygen mixture is used by deep sea divers in preference to nitrogen oxygen mixture because of its very low solubility in blood.

Answer 169

(C) (SSC CGL 2016) Exp: Water is used in hot water bag because it has high specific heat. The specific heat of water is 1 calorie/ gramºC or 4.186 joule/gramºC which is higher than any other common substance.

Answer 170

(D) (SSC CGL 2016) Exp: Magnesium metal in the form of Mg+2 ions are present in chlorophyll a, the green colour pigment of plants, which absorb light and is essential for photosynthesis.

Answer 171

(A) (SSC CGL 2016) Exp: When sodium bicarbonate (NaHCO3) is strongly heated it gives sodium carbonate. 2NaHCO3 Na2CO3 + CO2 + H2O

Answer 172

(C) (SSC CGL 2016) Exp: The most pure form of carbon among the options is graphite because other forms of elemental carbon like carbon black, coke and charcoal are all impure. Anthracite has 90-95% carbon content.

Answer 173

(C) (SSC CGL 2016) Exp: Charcoal is an amorphous allotropic form of carbon. Charcoal is highly porous substance and can adsorb many times their own volume of gases. Its adsorption capacity can be further increased by heating at 1273K in a current of super heated steam. Charcoal thus prepared is called activated charcoal.

Answer 174

(C) (SSC CGL 2016) Exp: Silica gel acts as drying agent. Silica gel is a amorphous form of silica or Silicon dioxide (SiO2). It is very porous and it contains about 4% water. To protect merchandise from moisture during storage, small packets of dry silica gel are placed in packing boxes.

Answer 175

(B) (SSC CGL 2016) Exp: Silver gets corroded by reacting with hydrogen Sulphide in the air to form black Silver Sulphide compound.

Answer 176

(C) (SSC CGL 2016) Exp: Silver metal has maximum thermal conductivity in the given options. Increasing order of thermal conductivity at 25ºC for various metals. Platinum < Iron < Tungsten < Aluminium < Gold < Copper < Silver.

Answer 177

(B) (SSC CGL 2016) Exp: Three main allotropic form of Phosphorous are (A) White phosphorous, (B) Red phosphorous (C) Black phosphorous. White phosphorous is more reactive than the other because of angular strain in P4 molecule where the angles are only 60° in other forms.

Answer 178

(A) (SSC CGL 2016) Exp: Magnesium is a constituent metal of chlorophyll molecule.

Answer 179

(D) (SSC CGL 2016) Exp:When chlorine gas is passed through dry slaked lime, bleaching powder (CaOCl2) is formed. It is also called chloride of lime. Its chemical name is Calcium OxyChloride. Ca(OH)2 + Cl2 CaOCl2+ H2O

Answer 180

(B) (SSC CGL 2016) Exp: White phosphorus (P4) has very low ignition temperature (303 K) and therefore it catches fire in air so it is generally stored in under water.

Answer 181

(A) (SSC CGL 2016) Exp: Argon is used to protect metal surfaces from oxidation during the welding of steel. It is used to provide an inert atmosphere in metallurgical processes.

Answer 182

(C) (SSC CGL 2016) Exp: The group 18 consist of elements He, Ne, Ar, Kr, Xe, and Rn. These gases at ordinary temperature do not have chemical reactivity and therefore, they are called inert gases.

Answer 183

(C) (SSC CGL 2016) Exp: Hydrogen is used as an efficient fuel because It has many advantages over conventional fossil fuels. It does not produce any pollution and releases larger energy per unit mass of fuel in comparison to gasolene and other fuels. 2H2 + O2 2H2O

Answer 184

(D) (SSC CGL 2016) Exp: In India, coal is the bulk of primary energy contributor with 56.90% share.

Answer 185

(A) (SSC CGL 2016) Exp: The purest form of water in nature is rain water.

Answer 186

(A) (SSC CGL 2016) Exp: Highest percentage of carbon is found in Anthracite coal. It contains 92-98% carbon.

Answer 187

(A) (SSC CGL 2016) Exp: Since only three electrons of each carbon are used in making hexagonal rings in graphite, fourth valence electron of each carbon is free to move. This makes graphite a good conductor of heat and electricity.

Answer 188

(C) (SSC CGL 2016) Exp: In the given options, activated coconut charcoal acts as best adsorbent. It has predominantly pores in micro pore range. Almost 85-90% surface are of a coconut shell exist as micropores. These small pores match the size of contaminant molecules in drinking water and therfore are very effective in trapping them.

Answer 189

(C) [SSC CHSL 2014] Exp: Mercury metal has the lowest melting point because it is found in liquid state at room temperature.

Answer 190

(D) (SSC CHSL 2016) Exp: Mercury metal has the lowest melting point because it is found in liquid state at room temperature.

Answer 191

(A) (SSC CGL 2016) Exp: Anthracite coal is much harder than other forms of coal, so it is known as hard coal. It contains about 90- 95% Carbon.

Answer 192

(D) (SSC CPO 2017) Exp: Osmium is the heaviest element in periodic table as it has the highest density.

Answer 193

(A) (SSC CPO 2017) Exp: Lithium is the lightest solid metal & has lowest density. Lithium is reactive alkali metal.

Answer 194

(A) (SSC CPO 2017) Exp: Potassium is the most reactive in nature. So, it is not found naturally in its elemental form. Due to its reactive nature, it is kept under the Kerosene oil.

Answer 195

(D) (SSC CPO 2017) Exp: Metals are hard, lustrous & malleable. Hardness:- Metals are hard due to Metallic bonding. Lustrous:- On exposure of light, metals emit electrons from its surface, so they are lustrous (shiny in appearance). Malleability:- Property of metals by which they can be converted into sheets. Conductor :- Metals are good conductor of heat & electricity due to free electrons.

Answer 196

(D) (SSC CGL 2017) Exp: Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) & Radon (Rn) are inert or noble gases due to completely filled stable configuration.

Answer 197

(C) (SSC CGL 2017) Exp: Property of a metal by which it can be beaten into sheets is called as Malleability. eg:- Aluminium, Gold & Silver can be beaten into sheets while potassium cannot be beaten into sheets because of its high reactivity.

Answer 198

(D) (SSC CGL 2017) Exp: 2 Mg + O2 2 MgO When Magnesium is burnt in presence of O2, a powder is formed i .e MgO (Magnesium Oxide)

Answer 199

(D) (SSC CGL 2017) Exp: Amphoteric metals reacts with sodium hydroxide to produce hydrogen gas. 2Al Amphoteric metal + 2NaOH Sodium hydroxide + 2H O2 Water 2NaAlO + 3H 2 2 Sodium aluminate Hydrogen gas

Answer 200

(D) (SSC CGL 2017) Exp: MgO + H2O Mg(OH)2 Mg(OH)2 is basic in nature & it is used as an antacid.

Answer 201

(C) (SSC CGL 2017) Exp: When Magnesium is burnt in air, it forms a white powder i.e. Magnesium oxide, which is called as Ash.

Answer 202

(C) (SSC CGL 2017) Exp: Ductility is a property of a metal by which it can be converted into wires. Gold is the most ductile & malleable metal.

Answer 203

(B) (SSC CGL 2017) Exp: The property of metals by which they can be beaten into thin sheets is called Malleability. Gold is the most ductile & malleable metal.

Answer 204

(C) (SSC CHSL 2016) Exp: Ethyl Alcohol or Ethanol (C2H5OH) is used for making liquors, medicines and as a fuel in aircrafts. Note: 1. 100% pure alcohol is known as absolute alcohol.

Answer 205

(A) (SSC CHSL 2016) Exp: Ethane gas has a slightly sweet taste.

Answer 206

(D) (SSC CHSL 2016) Exp: The chemical formula of Urea is NH2CONH2 or (NH2) 2CO. Urea was the first organic compound which is prepared by Friedrich Wohler in the laborary in 1828 from inorganic compound ammonium cyanate.

Answer 207

(C) (SSC CHSL 2016) Exp: Alkenes were earlier known as Olefins (Greek: Olefiant = oil forming) since the lower members of alkenes forms oily product on reaction with halogens such as chlorine and bromine.

Answer 208

(A) (SSC CHSL 2016) Exp: In decane 'Dec' represent 10 carbon atoms while 'ane' represent it is an alkane. General formula of alkane is CnH2n+2 where 'n' represents no. of carbon atoms. Decane - C10H2×10+2 = C10H22 So, 22 hydrogen atoms are present in Decane.

Answer 209

(C) (SSC CHSL 2016) Exp: Carcinogenic are the agents or substances which causes cancer. Benzene and most of the polynuclear aromatic hydrocarbons are Carcinogenic. Examples: 1,2 - Benzopyrene, 1,2 - benzanthracene etc.

Answer 210

(D) (SSC CHSL 2016) Exp: Hydrocarbons and their alkyl, alkenyl and alkynl derivatives which contain one or more-benzene rings either fused or isolated in their molecules are called aromatic hydrocarbons. They are also called arenes (Aromatic alkenes)

Answer 211

(C) (SSC CHSL 2016) Exp: Pentane (C5H12) has three structural isomers. 1. CH3 - CH2 - CH2 - CH2 - CH3 2. CH - 3 CH - CH - CH 2 3 CH3 3. CH 3 C CH 3 CH 3 CH 3

Answer 212

(B) (SSC CHSL 2016) Exp: Ethylene Glycol is used to prevent freezing of fuel in space crafts.

Answer 213

(B) (SSC CHSL 2016) Exp: Acetylene reacts with oxygen to produce oxyacetylene. Oxyacetylene flame is used to generate light, to weld metals.

Answer 214

(A) (SSC CHSL 2016) Exp: Chloroform undergoes oxidation in the presence of light and air to form phosgene (carbonyl chloride) CHCl3 + 1 2 O2 O Cl C Cl || - - + HCl Chloroform is stored in dark bottles to prevent the formation of phosgene, as it is highly poisonous.

Answer 215

(B) (SSC CHSL 2016) Exp: Benzene (phene), C6H6 was first discovered by Michael Faraday (1825).

Answer 216

(A) [SSC CHSL 2011] Exp: Methyl Alcohol or Methanol (CH3OH) is known as wood spirit. It is also known as wood alcohol because it was formerly obtained by the destructive distillation of wood.

Answer 217

(A) [SSC CGL Exam, 2014] Exp: The octane number of fuel is based on how two fuels ignite, under compression. Octane no of all fuels lies between n-Heptane and 2,2, 4- Tri Methyl pentane (Iso - octane). Octane number of n-Heptane is zero while isooctane has 100.

Answer 218

(B) [SSC CHSL Exam, 2012] Exp: The first time chloroform was used as anaesthetic by James Simpson. But it is rarely used for this purpose now because it causes extensive liver damage. Chloroform undergoes oxidation in the presence of light and air to form phosgene (carbonyl chloride).

Answer 219

(A) [SSC Steno Exam, 2005] Exp: The process of conversion of sugar into Alcohol (Ethanol) is known as Fermentation. C12H22O11 + H2O Invertase C6H12 O 6+ C6H12O6 (Sucrose) (Glucose) (Fructose) C6H12O6 Zymase 2C2H5OH+2CO2

Answer 220

(D) [SSC Sec off. 2007] Exp: Denaturated spirit or denaturated alcohol is commercial ethyl alcohol to which small amounts of very poisonous substances like pyridine or methyl alcohol has been added.

Answer 221

(A) [SSC CHSL 2012] Exp: Naphthalene is the largest single constituent (6 to 10%) of coal tar. Naphthalene as 'moth ball' has been used to protect woolen goods from moths.

Answer 222

(A) [SSC CGL Exam, 2006] Exp: 40% aqueous solution of formaldehyde (Methanal) is known as formalin. It is used as germicide, antiseptic and also for preserving biological specimens.

Answer 223

(A) [SSC MTS 2006] Exp: Isomer of ethyl alcohol (C2H5OH) is dimethyl ether (CH3OCH3). Isomers are the compounds having same molecular formula but differ from each other in physical or chemical properties.

Answer 224

(A) [SSC MTS 2006] Exp: Ethanol is obtained from the fermentation of starch. The process of conversion of starch, sugar to alcoholic products (Beer, Whisky and vodka etc.) in the presence of yeast or some bacteria is known as fermentation.

Answer 225

(D) [SSC CHSL 2013] Exp: Furan is a heterocyclic compound. Heterocycliccompounds are those cyclic compounds in which one or more of the ring carbons are replaced by another atom (hetero atom). Nitrogen, oxygen and sulphur are most common hetero atoms. eg. pyrrole, thiophene, pyridine, tetrahydrofuran etc.

Answer 226

(A) [SSC FCI 2012] Exp: Bagasse is sugarcane fibre waste left after juice extraction. It is used for production of paper.

Answer 227

(A) Exp: Upon hydrolysis, Aluminium carbide gives methane gas. Al4C3 + 12H2O 3CH4+ 4Al(OH)3

Answer 228

(B) [SSC CPO, CGL 2005, 06, 08] Exp: Ethylene gas is used for the artificial ripening of fruits. It is only gaseous plant hormone.

Answer 229

(A) Exp: Rectified spirit contains 95.6% of ethanol and 4.4% of H2O. It is purified by the means of repeated distillation called rectification.

Answer 230

(C) Exp: On warming with chloroform and alcoholic solution of KOH, primary amines (both aliphatic and aromatic) form isocyanides or carbylamines with extremely unpleasant smell. 3 R - NH - 3 3 2 2 CHCl KOH R NC KCl H O

Answer 231

(D) [SSC CHSL 2010] Exp: The gas that usually cause explosion in coal mines is methane (CH4). The coal miners call it fire damp because it forms explosive mixture with air.

Answer 232

(B) [SSC CGL 2011] Exp: Acetylene burns in an atmosphere of pure oxygen to produce extremely high temperature (3200°C). This flame is used for welding.

Answer 233

(A) Exp: Order of basic strength in aqueous solution depends not only upon electron releasing effect but also upon steric effect & Hydration effect.

Answer 234

(D) [SSC CHSL 2012] Exp: The process of conversion of carbon compounds (Organic) in alcohol by Micro organism is called fermentation.

Answer 235

(A) [SSC CGL 2014] Exp: Nitrous oxide (N2O) & Chloroform (CHCl3) are used as anaesthetic in medicines. Note: Ether (Diethyl ether) is also used as anaesthetic.

Answer 236

(D) Exp: Chloropicrin (CCl3NO2) or Nitrochloroform is the constituent of tear gas. It is currently used as fungicide, herbicide insecticide and broad spectrum antibiotics.

Answer 237

(D) [SSC CPO 2015] Exp: Benzene reacts with chlorine in the presence of ultraviolet light to form benzenehexachloride (BHC). BHC is a powerful insecticide. It is sold under the name Lindane.

Answer 238

(C) Exp: CH4 (Methane) is known as Marsh gas because it evolves as bubbles from marshy land by decaying of animals and plant materials.

Answer 239

(D) [SSC MTS 2013] Exp: 1% cold Alkaline potassium permanganate solution (KMnO4) is known as Baeyer's reagent.

Answer 240

(A) [SSC MTS 2014] Exp: Carbon compounds of Aldehyde group reacts with Fehling's solution and HCHO is a compound of Aldehyde group.

Answer 241

(C) (SSC CGL 2016) Exp: Molasses is a cheap source of glucose, fructose, and sucrose and it forms an excellent raw material for making ethyl alcohol. Today less than 10% of ethyl alcohol is made by this method. In India, molasses is still major source of ethyl alcohol.

Answer 242

(B) (SSC CGL 2016) Exp: Yeast cells convert sugar solution into alcohol by fermentation. Invertase and zymase enzymes participate in this process. C12H22O11+H2O Invertase C6H12O6+C6H12O6 (Glucose) (Fructose) C6H12O6 Zymase 2C2H5OH+2CO2 Glucose Ethyl alcohol

Answer 243

(B) (SSC CGL 2016) Exp: During fermentation of sugar ethyl alcohol (ethanol) is always formed. Fermentation of sugar takes place in presence of yeast cells.

Answer 244

(C) (SSC CGL 2016) Exp: Aldehydes are easily oxidised to corresponding acids with same no of carbon atoms with the help of oxidising agents such as acidified KMnO4 or acidified K2Cr2O7 solution. Reducing agents are easily oxidised itself and reduce other substances. Example. CH3CHO+|O| CH3COOH C6H5CHO + |O| C6H5COOH Since Aldehydes can be easily oxidized, they act as strong reducing agents.

Answer 245

(D) [SSC CHSL 2013] Exp: Glycerol is obtained from the process of Saponification it's a kind of sugar alcohol. Triglyceride+Sodium hydroxide Glycerol+3 Soap molecules

Answer 246

(A) (SSC CGL 2017) Exp: Phenol is also known as Carbolic acid. Its molecular formula is C6H5OH. It is used as anti-microbial agent.

Answer 247

(C) (SSC CHSL 2016) Exp: Kevlar is a polyamide which is used to make bulletproof vests. 1,4-diaminobenzene and terephthaloyl chloride react to form kevlar.

Answer 248

(D) (SSC CHSL 2016) Exp: Polyvinyl chloride (PVC) is polymerised product of vinyl chloride in the presence of benzoyl peroxide. PVC is a thermoplastic polymer. It is used for artificial floor covering.

Answer 249

(B) (SSC CHSL 2016) Exp: Nylon-66 is used for making bristles of brushes. It is a polymerised product (polyamides) of adipic acid and hexamethylene diamine.

Answer 250

(C) (SSC CHSL 2016) Exp: Natural rubber may be considered as a linear polymer of Isoprene (2-methyl-1, 3 butadiene). Natural rubber possesses elastic properties so, it is also termed as Elastomer. To improve physical properties a process of vulcanisation is carried out. This process consist of heating a mixture of raw rubber with sulphur and additive.

Answer 251

(C) (SSC CHSL 2016) Exp: In the given options, Neoprene is a synthetic rubber. Neoprene or polychloroprene is polymer of chloroprene.

Answer 252

(B) (SSC CHSL 2016) Exp: Milbemycin is used as broad spectrum antiparasite. It is used in the eradication of agricultural pests.

Answer 253

(A) (SSC CHSL 2016) Exp: The expanded form of PET or PETE is Polyethylene terephthalate. Its commercial name is Terylene. It is also used for making clothes and helmets.

Answer 254

(A) (SSC CHSL 2016) Exp: Saponification is a process that produces soap. In chemistry, soaps are sodium or potassium salts of higher fatty acids like stearic acid, palmitic acid, Oleic acid etc.

Answer 255

(C) (SSC CHSL 2016) Exp: Teflon represents polytetrafluoro ethylene (PTFE). It is a polymer of Tetrafluoro ethylene. It is used for making nonstick cooking utensils.

Answer 256

(B) [SSC See off. 2006] Exp: Bakelite is formed by condensation reaction of urea & formaldehyde. It is a thermosetting polymer (the polymer which becomes hard on heating).

Answer 257

(C)Exp: Cellulose diacetate is also known as Rayon. It is obtained by the acylation of cellulose (natural polymer) with acetic anhydride in the presence of sulphuric acid. It is a semi synthetic polymer. Semisynthetic polymers are obtained from natural polymers by subjecting them to some chemical process.

Answer 258

(A) Exp: Barbituric acid and its derivatives are well known as Tranquilizers (medical drug, which reduce tension or anxiety).

Answer 259

(B) Exp: The helical structure of proteins has been confirmed by X-rays diffraction. In the helix structure, NH group of one unit is linked to CO group by hydrogen bonding. The hydrogen bonds hold the helix in position.

Answer 260

(B) Exp: Galactose (C6H12O6) is a monosaccharide. Monosaccharide have general formula (CnH2nOn). In monosaccharides, ratio of carbon, hydrogen and oxygen is 1: 2: 1. Disaccharide gives two molecules of monosaccharide on hydrolysis.

Answer 261

(B) Exp: Saccharides which reduce fehling solution, Tollen's reagent or Benedict's solution are called reducing sugars while those which fail to respond to those reactions are termed as non reducing sugars. ex: Sucrose, Starch, Cellulose, Glycogen

Answer 262

(A) Exp: The biodegradable polymer are the polymers which are degraded by the micro-organisms within a suitable period of time. Ex: Polyglycolic acid (PGA), polyhydroxy butyrate (PHB).

Answer 263

(D) [SSC MTS 2008] Exp: Nylon was discovered by American chemist Dr. wallac H. Carothers in 1935. Nylon is the material used in parachutes.

Answer 264

(B) [SSC CPO 2012] Exp: PVC (Polyvinyl Chloride) is formed by the polymerization of vinyl chloride. It is a homopolymer. It is used for making rain coats, water pipes and hand bags.

Answer 265

(A) [SSC Sec. officer 2006] Exp: Polyethene (Polythene) is a polymer of ethylene. It is a thermoplastic.

Answer 266

(B) Exp: Cellulose is a natural polymer. It is a polymer of glucose. Some other natural polymers are protein, silk, nucleic acid, rubber, polysaccharides.

Answer 267

(B) [SSC CGL 2012] Exp: Glycogen, cellulose and starch are the polymers of glucose. All are polysaccharides.

Answer 268

(A) Exp: Sulphur element is used for vulcanization of the rubber. On vulcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened. 5% of sulphur is used for manufacturing of rubber tyres.

Answer 269

(A) [SSC CGL Exam, 2014] Exp: The process of heating of rubber with sulphur between 373K to 415K to increase it quality is known as Vulcanisation.

Answer 270

(A) [SSC MTS 2011, SSC CGL 2006] Exp: Natural rubber is a polymer of Isoprene (2- methyl - 1, 3- butadiene). All the double bonds in rubber are cis, hence natural rubber is cis-polyisoprene. Main source of rubber is Hevea brasiliensis tree.

Answer 271

(A) [SSC Steno 2011] Exp: Bakelite are polymers of phenol and formaldehyde. It is a cross linked polymer. It is used for making combs electrical switches, handles of various utensils etc.

Answer 272

(C) [SSC LDC Exam, 2005] Exp: Polystyrene is a synthetic polymer. It is a polymer of styrene. It is a thermosplastic polymer. It is used for making toys, radio & T.V. cabinets, wrapping material.

Answer 273

(B) [SSC CGL Exam, 2005] Exp: Paraffin wax is known as petroleum wax. It is a mixture of higher hydrocarbons. It is obtained from petroleum, coal or oil shale. Honey wax is obtained from honey bee. Carnauba also called Brazil wax and palm wax is obtained from palm leaves.

Answer 274

(A) [SSC Tax Asst. 2008] Exp: Wax used for making candles is chemically a mixture of aliphatic hydrocarbons.

Answer 275

(C) [SSC CPO 2007] Exp: Petroleum is a mixture made up of mostly hydrocarbons. It consists alkanes (37-70%), cycloalkanes (16-64%) and aromatic hydrocarbons (8-15%). Its unpleasent odour is due to sulphur compounds.

Answer 276

(D) [SSC CGL 2011] Exp: A mixture of liquid hydrogen and liquid oxygen is used as a fuel in rockets.

Answer 277

(A) [SSC CGL 2011] Exp: Glycol is also called Ethylene Glycol, it is a dihydric alcohol. It is added to aviation gasoline because it prevents freezing of petrol. It can be used as an antifreeze compound in car radiators.

Answer 278

(C) [SSC MTS 2006] Exp: In the presence of enzyme invertase, Sucrose is converted into glucose and fructose by aqueous hydrolysis. Sucrose (C12H22O11) is a disaccharide sugar. It is known as sugar of sugarcane.

Answer 279

(B) [SSC CHSL 2014] Exp: Glucose is a type of Hexose sugar. Its chemical formula is C6H12O6.

Answer 280

(A) [SSC CGL 2012] Exp: Tranquilizers are used for the treatment of stress and mild or even severe mental disease. They form an essential component of sleeping pills.

Answer 281

(A) [SSC CGL 2014] Exp: Allopathy is a medical practice which involves the treatment of diseases by using synthetic drug or chemicals.

Answer 282

(C)Exp: The substance which is used to kill rat is called rodenticide. Examples:- Zinc phosphide, Thallium sulphate, Sodium monochloroacetate, Sodium fluoroacetate.

Answer 283

(A) [SSC Steno 2005] Exp: Chlorine in the concentration of 0.2 to 0.4 ppm in aqueous solution is disinfectant. Chlorine destroys the microbes present in water

Answer 284

(D) [SSC Tax Asst., MTS 2002, 06 & 08] Exp: Food preservatives prevent spoilage of food due to microbial growth. Eg:- Sodium benzoate

Answer 285

(D) [SSC CGL 2006] Exp: Disinfectant are substances which are applied on the surface of non-living objects to destroy microbes. Chlorine in the concentration of 0.2 to 0.4 ppm in aqueous solution acts as disinfectant. Chlorine destroy the microbes present in water.

Answer 286

(C) [SSC CPO 2012] Exp: Coppersulphate (CuSO4) - Antifungal Urea (NH2CONH2) - Fertilizer Penicillin - Antibiotic Malathion - Insecticide

Answer 287

(A) [SSC CHSL 2012] Exp: Saponification is the alkaline hydrolysis of the fatty acid esters. Example: The chemical reaction between fatty acid and sodium hydroxide is a saponification reaction. Triglyceride + Sodium hydroxide Glycerol + 3 soap molecules.

Answer 288

(B) [SSC Sec. off. - 2006] Exp: NaOH (Sodium Hydroxide) is a white solid crystal. Its aqueous solution is smooth as same as soap. It is also known as caustic soda. It is also used in the manufacturing of soap. Hydrolysis of fatty acids with caustic soda forms soap and glycerol and this process is known as 'Saponification'.

Answer 289

(A) [SSC CPO 2008] Exp: Saponification is the alkaline hydrolysis of the fatty acid esters. Example: The chemical reaction between fatty and sodium hydroxide is a saponification reaction. Triglyceride + Sodium hydroxide Glycerol + 3 soap molecules.

Answer 290

(C) (SSC CGL 2016) Exp: Glycol (Ethylene glycol) and Terephthalic acid form condensation product is called Terylene or Dacron.

Answer 291

(D) (SSC CGL 2016) Exp: Teflon or Polytetrafluoro ethylene (PTFE) is prepared by the polymerisation of tetrafluoro ethylene in the presence of benzoyl peroxide. It is used for making nonstick surfaces of cooking p At high temperature (573K) it may crack.

Answer 292

(D) [SSC CGL 2013] Exp: Dettol contains the antiseptic compound enloroxylenol. Dettol is a mixture of chloroxylenol and terpineol dissolved in a suitable solvent.

Answer 293

(C)Exp: KMnO4 (Potassium Permanganate) can be used as a disinfectant (germicide).It is used to purify well water. It is commonly known as Red Medicine or Lal dawa.

Answer 294

(A) [SSC Tax Asst. 2006] Exp: Tincture of iodine or Iodine tincture is an antiseptic. 2 - 7% elemental iodine along with potassium iodide or sodium iodide dissolved in mixture of ethanol & water.

Answer 295

(D) (SSC CGL 2016) Exp: Terylene is also known as Dacron and it is the condensation product of ethylene glycol and terephthalic Acid. Terylene is used in the manufacture of terycot, terywool & terysilk, magnetic recording tapes, conveyer belts, aprons for industrial workers.

Answer 296

(D) (SSC CGL 2016) Exp: Silk is natural protein fibre, made by silkworm. It is one of the strongest natural fibres. The rearing of silkworm is known as Sericulture.

Answer 297

(D) (SSC CGL 2016) Exp: Natural polymers occur in nature mostly in plants and animals. Examples - Starch, cellulose, proteins natural rubber, nucleic acids etc.

Answer 298

(C) (SSC CGL 2016) Exp: Synthetic detergents are normally prepared from petrochemicals, fats and oils.

Answer 299

(D) (SSC CPO 2017) Exp: Argon gas is used in bulbs because argon is an inert gas & doesn't react even at higher temperatures.

Answer 300

(B) (SSC CPO 2017) Exp: Chemical formula of Tear gas is C10H5ClN2. So, chlorine is component of tear gas LPG is a mixture of flammable hydrocarbon gases including propane & butane while Gobar gas mainly consists of methane.

Answer 301

(D) (SSC CPO 2017) Exp: Silicon is used in solar panels, optical glass & IC chips as silicon is a semi-conductor. But in ink, silicon is not present.

Answer 302

(A) (SSC CPO 2017) Exp: Fire Extinguishers are the devices which are used to control fire. From the given options, Carbon dioxide is used in fire extinguisher.

Answer 303

(A) (SSC CPO 2017) Exp: Chlorine on reaction with water releases nascent Oxygen. Cl2 + H2O HCl + HOCl HOCl HCl + [O] This nascent oxygen reacts with coloured matter to make it colourless. Coloured matter + [O] Colourless matter + H2O. Thus, chlorine has its bleaching action due to Oxidation phenomenon.

Answer 304

(B) (SSC CPO 2017) Exp: Ethylene is a gaseous plant hormone. It is used for ripening of fruits. Ethylene is also called as ethene (CH2 = CH2).

Answer 305

(C) (SSC CPO 2017) Exp: Biogas is produced from cattle dung in a biogas plant i.e. commonly known as Gobar Gas. Gobar gas mainly consists of Methane (CH4).

Answer 306

(B) (SSC CPO 2017) Exp: Rock salt is Sodium Chloride (NaCl). So, Rock salt contains sodium mineral.

Answer 307

(C) (SSC CPO 2017) Exp: Fertilizers are the substance which are added to soil to improve its nutrient quality (fertility). Nitrogen (N), Potassium (K) & Phosphorous (P) are the main three constituents of fertilizers. Therefore, they are called as NPK fertilizers

Answer 308

(A) (SSC CPO 2017) Exp: Formation of compost by using earth worms (Red Earth worms) is called as Vermicompost. It is a organic Manure or organic fertilizer.

Answer 309

(A) (SSC CGL 2017) Exp: Dry ice is solid CO2. At atmospheric pressure solid CO2 is converted directly into vapour without a liquid phase

Answer 310

(C) (SSC CGL 2017) Exp: PET refers to polyethylene terephthalate. It is a thermoplastic polymer. It is a condensation polymer of terephthalic acid & ethylene glycol. PET is used for making bottles, synthetic fibres and coating etc.

Answer 311

(B) (SSC CGL 2017) Exp: Formic acid or Methanoic acid (HCOOH) is released when a red ant bites.

Answer 312

(D) (SSC CGL 2017) Exp: Tungsten is generally used for making filaments of bulb because it has very high melting point (3422oC). Symbol of tungsten is W.

Answer 313

(C) (SSC CGL 2017) Exp: Potassium nitrate is used for manufacturing the fire crackers because it is a good oxidant. It helps in oxidation of fire work mixture.

Answer 314

(A) (SSC CGL 2017) Exp: Antacids are basic substances which neutralise the stomach acidity on ingestion. They are used to treat Indigestion. eg:- Mg(OH)2

Answer 315

(A) (SSC CGL 2017) Exp: Sodium hydroxide is found in soaps. Soaps are formed by reacting a base with fatty acid. Sodium hydroxide + Glycerol Tristearate Sodium stearate (soap) + Glycerol

Answer 316

(B) (SSC CGL 2017) Exp: Rayon is also known as Artificial silk because it resembles silk. Rayon is a synthetic fibre. It is cheaper than silk. Rayon is used for making fibres, clothes etc.

Answer 317

(C)Exp: Fire extinguishers are used to stop the fire. From the given options, fire extinguishers contain CO2, i.e. heavier than oxygen which stops fire.

Answer 318

(C) (SSC CGL 2017) Exp: Salt is obtained by evaporation of seawater as seawater contains sodium chloride, magnesium chloride etc.

Answer 319

(D) (SSC CGL 2017) Exp: Friction between match box surface & match stick lights up fire. Tip of match has potassium chlorate (an oxidant), sulphur, starch & glue. Striking surface has red phosphorous.

Answer 320

(D) (SSC CGL 2017) Exp: A nylon thread is actually stronger than a steel wire because nylon thread can support more weight compared to steel wire of same thickness.

Answer 321

(D) (SSC CGL 2017) Exp: Fabric made from polyester does not get wrinkled easily because it has high wrinkle resistant.

Answer 322

(C) (SSC CHSL 2016) Exp: Chlorofluorocarbon and nitric oxide have been found to be the most responsible for depletion of ozone and creating ozone hole. Ozone hole was discovered in 1984 by British Antarctic survey scientist, Joseph Farman, Brain Gardiner and Jonathan shanklin.

Answer 323

(C) (SSC CHSL 2016) Exp: Bhopal gas tragedy was caused by (MIC) methyl isocyanate (CH3NCO) on december 2, 1984 in Bhopal (M.P) in the Union Carbide factory. MIC is used for manufacturing the insecticide, Carbaryl.

Answer 324

(B) (SSC CHSL 2016) Exp: The great smog of 1952 was a severe air pollution event which affected London. London smog or classical smog or sulphurous smog:- This type of smog was first observed in London in December 1952 which killed many people. It is formed due to presence of SO2 and humidity in the air which combine to form H2SO4. It is formed in the early morning hours of winter month. smoke + fog = smog

Answer 325

(B) (SSC CHSL 2016) Exp: Carbon monoxide is formed by incomplete combustion of carbon and carbon containing fuels. 2C + O2 2CO This type of incomplete combustion occurs during burning of petrol or diesel in automobiles therefore CO is always present in automobile exhausts.

Answer 326

(C) (SSC CHSL 2016) Exp: Greenhouse gases are: Carbon dioxide (CO2)-60%, Methane (CH4)-20% Chlorofluoro carbon (CFC)-14%, Nitrous oxide (N2O)-6%

Answer 327

(C) (SSC CHSL 2016) Exp: Haemoglobin has the highest affinity with CO. CO is able to form a complex with haemoglobin (carboxyhaemoglobin) which is about 300 times more stable than the oxyhaemoglobin.

Answer 328

(B) (SSC CHSL 2016) Exp: Distilled water has no impurity. Distillation is a method of water purification.

Answer 329

(B) (SSC CHSL 2016) Exp: UV rays cause burning or tanning of skin. UV rays damage DNA of skin & cause cancer.

Answer 330

(C) (SSC CHSL 2016) Exp: CCl3F is Freon. Freons are the chlorofluorocarbon (CFCs) or hydrochlorofluorocarbons (HCFCs) compounds. They are used as refrigerants and as aerosol propellants. Freons are responsible for Ozone depletion

Answer 331

(C) (SSC CHSL 2016) Exp: Stratosphere is a second layer of Earth's atmosphere, present above troposphere layer.

Answer 332

(C) (SSC CHSL 2016) Exp: Greenhouse gases are: Carbon dioxide (CO2)-60%, Methane (CH4)-20% Chlorofluoro carbon (CFC)-14%, Nitrous oxide (N2O)-6%

Answer 333

(C) (SSC CHSL 2016) Exp: Water vapour CO2, CH4, N2O, Ozone are Green House Gases which deplete Ozone layer.

Answer 334

(D) (SSC CHSL 2016) Exp: Water vapour CO2, CH4, N2O, Ozone are Green House Gases.

Answer 335

(D) (SSC CHSL 2016) Exp: Exp: Water vapour CO2, CH4, N2O, Ozone (O3) are Green House Gases.

Answer 336

(D) (SSC CHSL 2016) Exp: CClF3 is Freon. freons are the chlorofluorocarbon (CFCs) or hydrochlorofluorocarbons (HCFCs) compounds. They are used as refrigerants and as aerosol propellants. Freons are responsible for Ozone depletion. Water vapour CO2, CH4, N2O, Ozone are Green House Gases.

Answer 337

(C) (SSC CHSL 2016) Exp: CHCl2F is Freon. Freons are the chlorofluorocarbon (CFCs) or hydrochlorofluorocarbons (HCFCs) compounds. They are used as refrigerants and as aerosol propellants. Freons deplete Ozone layer.

Answer 338

(B) (SSC CHSL 2016) Exp: Freons are the chlorofluorocarbon (CFCs) or hydrochlorofluorocarbons (HCFCs) compounds. They are used as refrigerants and as aerosol propellants. Freons deplete Ozone layer.

Answer 339

(A) (SSC CHSL 2016) Exp: Water vapour CO2, CH4, N2O, Ozone are Green House Gases which deplete Ozone layer.

Answer 340

(C) (SSC CHSL 2016) Exp: In the given options, Argon is an inert gas 0.93%. Argon is present in air. CO2 = 0.04%.

Answer 341

(A) (SSC CHSL 2016) Exp: CH2ClF is freon. Freons are the chlorofluorocarbon (CFCs) or hydrochlorofluorocarbons (HCFCs). They are used as refrigerants and as aerosol propellants. Freons are responsible for Ozone depletion

Answer 342

(D) (SSC CHSL 2016) Exp: Methane (CH4) is the simplest hydrocarbon. It is released into the air in large quantities by the anaerobic decomposition of organic matter in soil, water and sediments. Bacteria 2CH O CH CO 2 4 2 Domestic animals contribute a very huge amount of methane into the air.

Answer 343

(C) (SSC CHSL 2016) Exp: DO in river is 3-5 ppm. (DO) Dissolved oxygen is used to check the pollution level. Greater the DO less will be the pollution.

Answer 344

(B)Exp: Lichens show symbiotic relationship between algae and fungi. If air is very badly polluted with sulphur dioxide there may be no lichens present.

Answer 345

(A) (SSC CHSL 2016) Exp: Determination of BOD of a sample of water requires 20-30 days for the complete decomposition of waste. Therefore usually we determine BOD5, i.e. the amount of oxygen consumed in 5 days. Pure water has 3-5 ppm BOD. The untreated municipal sewage has BOD5 of 100-400 ppm.

Answer 346

(C) (SSC CHSL 2016) Exp: Chlorofluoro carbon (CFC) i.e. compounds containing chlorine, fluorine and carbon commonly known as freon. Freons are responsible for Ozone depletion.

Answer 347

(A) (SSC CHSL 2016) Exp: In the given options, only water vapour gas contributes more. But ozone contribution is negligible.

Answer 348

(C) (SSC CHSL 2016) Exp: In the stratosphere (11-50 km), the oxygen started partially being converted into ozone. Now at an altitude of 25 - 30 km, we have a layer in which the concentration of ozone is about 10ppm. It is called ozone layer.

Answer 349

(A) (SSC CHSL 2016) Exp: Methyl isocyanate (CH3CNO) gas was leaked in the Bhopal gas tragedy in December 1984.

Answer 350

(D) [SSC MTS 2013] Exp: If sewage water is completely oxidized then Nitrogen gets converted into nitrates.

Answer 351

(C) [SSC CGL 2015] Exp: Catalytic converters are generally made from transition metals which convert toxic gases to less toxic pollutants.

Answer 352

(A) [SSC CHSL 2013] Exp: The gas causes acid rain in industrial areas is sulphur dioxide (SO2). SO2 oxidation SO3 SO3 + H2O H2SO4

Answer 353

(B) [SSC FCI 2012] Exp: Acid rain in the environment is caused by the higher concentration of SO2 & NO2. Both gases react with water to form H2SO4 & HNO3. H2SO4 contributed 60-70% and HNO3 contributes 30-40%. When the pH of rain water falls below 5.6, it becomes acid rain.

Answer 354

(C) [SSC CPO 2012] Exp: Portland cement contains 35% of fly ash, which causes air Pollution.

Answer 355

(B) [SSC CHSL 2010] Exp: Disease caused by lead poisoning is known as Plumbism. Abdominal pain, weight loss, delay in development are some symptoms.

Answer 356

(D) [SSC CHSL 2011] Exp: According to the notification published by WHO 'Guidelines for drinking water quality' in 2011 (4th edition), Maximum permissible concentration of Copper in drinking water is 2.0mg/L

Answer 357

(B) [SSC CGL 2013] Exp: Copper and Zinc combined to form Brass. Copper reacts with Hydrogen sulphide to form a black coloured compound copper sulphide and as a result of it brass gets discoloured

Answer 358

(A) [SSC Steno Exam, 2015] Exp: The main Moto of pollution controlling programme is to reduce the disposal of oxygen consuming waste in rivers. The pollutant which decreases the amount of oxygen in water is known as Oxygen consumers.

Answer 359

(B) [SSC Steno Exam, 2012] Exp: Small solid particles and liquid droplets suspended in air are collectively called as Suspended particles (Particulates). Sources of particulates- (A) Natural sources- Volcanic eruption, grinding, blowing of dust and soil by the wind spraying of salts by seas and oceans etc. (B) Man made sources - soot, flyash

Answer 360

(C) [SSC CGL Exam, 2015] Exp: Brown air word is used for photochemical smog Photochemical smog is obtained by the reaction of air pollutant and sunlight. Its main constituent gases are Hydrocarbon, Nitrogen oxide, PAN (Peroxyl acetyl Nitrate).

Answer 361

(A) [SSC Steno 2014] Exp: Taj Mahal is affected by acid rain which mainly contains H2SO4 & HNO3. SO2 & NO2 react with rain water to form H2SO4 & HNO3 respectively.

Answer 362

(D) [SSC Steno Exam, 2014] Exp: Automobile exhausts harmful compounds such as carbon dioxide, carbon monoxide, smoke, Nitrogen oxide, sulphur dioxide etc.

Answer 363

(D) [SSC MTS 2013] Exp: Sulphur dioxide pollution can be controlled in a number of ways as follows- (i) By using Low sulphur or sulphur free fuels like natural gas. (ii) By removing sulphur from the fuel (eg:- from fuel oil) before burning. (iii)By making sulphur-free Liquified gaseous fuel from coal.

Answer 364

(B) [SSC Steno 2011, SSC CHSL 2010] Exp: Pyrites ores are sulphide of metals. Burning of pyrite ore gives out sulphur dixoide gas. The SO2 produced, is ultilised for the manufacturing of H2SO4. e.g. Iron pyrite (FeS2), Copper pyrites (CuFeS2). 44. Disadvantage of using DDT as pesticide is - (A) It becomes ineffective after some time (B) Not easily degradable in nature (C) Less effective than others (D) Its High cost (B) [SSC CHSL 2012] Exp: As a pesticide DDT does not decompose easily in nature while its concentration goes on increasing from one level to another in a food chain is known as Bio Magnification.

Answer 365

(D) [SSC Steno 2012] Exp: PAN (Peroxyl acetyl Nitrate) is a macro pollutant. It is a pollutant present in photochemical smog.

Answer 366

(B) [SSC CGL Exam, 2015] Exp: PAN (Peroxyl acetyl Nitrate) is a macro pollutant. It is a powerful eye & respiratory irritant present in photo chemical smog.

Answer 367

(D) [SSC CGL Exam, 2015] Exp: Photochemical smog is the result of reaction of (NO2) Nitrogen dioxide and vapourised compounds in the presence of sunlight. Following conditions are necessary for its formation. 1. Sunlight 2. Nitrogen dioxide 3. Temperature greater than 18ºC By the result of this reaction toxic constituent peroxylacetyl Nitrate is produced.

Answer 368

(A) [SSC MTS 2014] Exp: Car and other automobiles exhaust mainly contains CO, lead and SO2 and out of these CO is the most toxic.

Answer 369

(A) [SSC CHSL 2010] Exp: Lead is the pollutant exhausted from motor car that causes mental disease.

Answer 370

(D) [SSC CGL 2012] Exp: Accident at Chernobyl nuclear power plant occurs on April 26 in 1986.

Answer 371

(B) Exp: The marble cancer refers to the corrosion of building and statues made up of marbles by the action of sulphuric acid and Nitric acid. Acid rain is the cause of 'Marble Cancer' of Taj Mahal. Marble cancer causes disintegration and yellowing of the building or statue. Taj Mahal is loosing its white shine because of marble cancer.

Answer 372

(C) [SSC CPO Exam, 2008] Exp: Nitrogen is present in 78%, oxygen is 21% and carbon dioxide, water vapour and Noble gases are 1%. Chlorine is not the part of atmosphere.

Answer 373

(D) [SSC MTS 2006] Exp: The chlorofluoro carbon compounds of methane and ethane are collectively known as freon. They are used as refrigerants and as aerosol propellants. Freons are responsible for Ozone depletion. Freon -12 (CCl2F2) is one of the most common freon in industrial use.

Answer 374

(D) [SSC CHSL 2011] Exp: Black lung disease is caused by long exposure to coal dust. It is common in coal miners and others who works with in coal industry.

Answer 375

(B) [SSC CHSL Exam, 2013] Exp: Lichens are indicator of air pollution mainly SO2 gas. A lichen consists of an Alga and a fungus living together in a symbiotic relationship. The Alga by photsynthesis produce food while the fungus protect the Alga and provides water and minerals to it. The fungus forms the main body of lichens.

Answer 376

(D) [SSC Tax Asst. Exam,2009] Exp: Combustion of sulphur containing coal and oil fuel in the thermal power plant produce SO2 gas. SO2 at a concentration of 5ppm causes throat and eye irritation resulting into cough tears and redness in eyes. It causes breath-lessness and affects larynx. (Voice box).

Answer 377

(D) [SSC Tax Asst. 2006] Exp: Acid rain contains about 60-70% H2SO4 & 30-40% HNO3.

Answer 378

(C)Exp: Nitrous oxide reacts with volatile organic compounds (except methane) to form a Peroxylacetyl nitrates or PAN a third component of smog. PAN makes smog more irritating to eyes.

Answer 379

(D) [SSC CGL 2014] OR

Answer 380

(C) [SSC CPO 2015] Exp: Acid rain is caused by the gaseous pollutant SO2 and NO2 present in atmosphere. In air, Sulphur dioxide (SO2) react with water (H2O) to form sulphuric acid (H2SO4) and Nitrogen dioxide (NO2) react with water to form Nitric acid (HNO3). Acid rain has pH less than 5.6.

Answer 381

(C) Exp: It is a mixture of a number of irritation causing compounds like NO2, O3, PAN, aldehydes, ketones, hydrocarbons and CO. It is oxidizing in character.

Answer 382

(B) Exp: Carbon monoxide gas is most toxic from the given options. It is produced by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhausts are the largest source of carbon monoxide. It accounts for over 50% of the total air pollution. Another source of air pollution is cigarette smoke. It reduces the oxygen carrying capacity of blood.

Answer 383

(B) [SSC Tax Asst. 2008] Exp: Carbon monoxide is main air pollutant. Carbon monoxide reduces the oxygen carrying capacity of blood and nicotine is Carcinogenic. (Cancer producing substance).

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