Organics Week 2 Flashcards

1
Q

What is a nucleophile?

A

A nucleophile is an atom or molecule that donates a pair of electrons to form a new covalent bond with an electron-deficient species, such as a carbon atom in a halogenoalkane. Nucleophiles are characterized by their electron-rich nature and their ability to participate in nucleophilic substitution reactions.

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2
Q

What are HFC’s?

A

HFCs (hydrofluorocarbons) are a class of chemical compounds that contain hydrogen, fluorine, and carbon atoms. They are used as alternatives to CFCs in refrigeration and air conditioning systems.

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3
Q

What is elimination?

A

Elimination is a type of chemical reaction in which a small molecule, often water, is removed from a molecule. This process typically involves the removal of a leaving group and the formation of a double bond or pi bond.

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4
Q

What is a halogenoalkane?

A

A halogenoalkane, also known as a haloalkane or alkyl halide, is an organic compound that contains a halogen atom (fluorine, chlorine, bromine, or iodine) bonded to a carbon atom. Halogenoalkanes are commonly used in organic synthesis and serve as starting materials for various chemical reactions

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5
Q

What is an elimination reaction?

A

An elimination reaction is a type of chemical reaction in which a small molecule, such as water or a hydrogen halide, is removed from a molecule, resulting in the formation of a double bond or pi bond. Elimination reactions are commonly observed in organic chemistry and can lead to the formation of alkenes or other unsaturated compounds.

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6
Q

What is a secondary haloalkane?

A

A secondary halogenoalkane is a halogenoalkane in which the carbon atom bonded to the halogen is directly connected to two other carbon atoms. It is classified as secondary because it has two carbon atoms attached to the carbon adjacent to the halogen.

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7
Q

What is ammonia?

A

Ammonia (NH3) is a colorless gas composed of one nitrogen atom bonded to three hydrogen atoms. It acts as a nucleophile in nucleophilic substitution reactions with halogenoalkanes, resulting in the replacement of the halogen atom with an amino group.

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8
Q

What is hydrolysis?

A

Hydrolysis is a chemical reaction in which a compound reacts with water to form two or more new compounds. In the context of halogenoalkanes, hydrolysis refers to the reaction of a halogenoalkane with water, resulting in the formation of an alcohol and a hydrogen halide.

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9
Q

What is an ionic equation?

A

An ionic equation is a chemical equation that shows only the species that are involved in a chemical reaction and their respective charges. It represents the transfer of ions between reactants and products, highlighting the formation or dissociation of ions.

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10
Q

What is a cyanide ion?

A

The cyanide ion (CN-) is a negatively charged molecule consisting of a carbon atom triple-bonded to a nitrogen atom. It acts as a nucleophile in nucleophilic substitution reactions with halogenoalkanes, resulting in the replacement of the halogen atom with a cyanide group

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11
Q

What are CFC’s?

A

CFCs (chlorofluorocarbons) are a class of man-made chemical compounds that contain chlorine, fluorine, and carbon atoms. They were widely used as refrigerants, propellants, and solvents.

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12
Q

What is a primary halolkane?

A

A primary halogenoalkane is a halogenoalkane in which the carbon atom bonded to the halogen is directly connected to only one other carbon atom. It is classified as primary because it has the fewest number of carbon atoms attached to the carbon adjacent to the halogen.

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13
Q

What is a tertiary haloalkane?

A

A tertiary halogenoalkane is a halogenoalkane in which the carbon atom bonded to the halogen is directly connected to three other carbon atoms. It is classified as tertiary because it has three carbon atoms attached to the carbon adjacent to the halogen.

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14
Q

What is nucleophilic substitution?

A

Nucleophilic substitution is a type of chemical reaction in which a nucleophile replaces a leaving group in a molecule. The nucleophile donates a pair of electrons to the carbon atom, resulting in the formation of a new bond.

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15
Q

What is the result of hydrolysis reactions of halogenoalkanes?

A

Hydrolysis reactions of halogenoalkanes involve the substitution of a halogen atom with an -OH group to form an alcohol.

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16
Q

How can the reactivity of haloalkanes be compared?

A

The reactivity of haloalkanes can be compared by the rate of formation of a precipitate of silver halide.

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17
Q

What do nucleophilic substitution and elimination reactions involve?

A

Nucleophilic substitution and elimination reactions involve swapping a halogen for another atom or group.

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18
Q

How can haloalkanes be classified?

A

Haloalkanes can be classified as primary, secondary, or tertiary based on the number of alkyl groups attached to the carbon next to the halogen.

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19
Q

Why do tertiary halogenoalkanes undergo elimination reactions?

A

Tertiary halogenoalkanes undergo elimination due to the stability of the tertiary carbocation.

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20
Q

How are haloalkanes named?

A

Haloalkanes are named by using a prefix to indicate the halogen atom and listing substituents alphabetically.

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21
Q

What are the different types of nucleophilic substitution reactions that can convert halogenoalkanes into other compounds?

A

Nucleophilic substitution reactions with aqueous hydroxide ions, cyanide ions, or ammonia can convert halogenoalkanes into alcohols, nitriles, or amines, respectively.

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22
Q

What caused the ozone layer hole and what measures have been taken to address it?

A

Man-made CFCs caused an ozone layer hole, but legislation and alternative compounds have been developed.

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23
Q

What are the harmful effects of using halogenoalkanes as solvents?

A

Halogenoalkanes can be used as solvents, but their harmful effects have led to reduced use.

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24
Q

What is involved in nucleophilic substitution and elimination reactions of halogenoalkanes?

A

Nucleophilic substitution and elimination reactions of halogenoalkanes involve the removal of a small molecule, often water, depending on the solvent used.

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25
Q

What is a chain reaction?

A

A chain reaction is a chemical reaction in which the products of one reaction step become the reactants of the next step, leading to a self-sustaining process. In the context of ozone depletion, the destruction of ozone molecules by chlorine radicals is an example of a chain reaction.

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26
Q

What is ozone?

A

Ozone is a molecule composed of three oxygen atoms (O3). It is naturally present in the Earth’s upper atmosphere, forming a layer known as the ozone layer.

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27
Q

What are HFC’s?

A

Hydrofluorocarbons (HFCs) are man-made chemical compounds that have been developed as alternatives to chlorofluorocarbons (CFCs) due to their lower ozone depletion potential. HFCs are composed of hydrogen, fluorine, and carbon atoms.

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28
Q

What is UV radiation?

A

UV radiation, or ultraviolet radiation, is a type of electromagnetic radiation emitted by the sun. It is invisible to the human eye but can have harmful effects on living organisms.

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29
Q

What are CFC’s?

A

Chlorofluorocarbons (CFCs) are man-made chemical compounds that were commonly used in various industrial and consumer applications, such as refrigeration, air conditioning, and aerosol propellants. CFCs are composed of carbon, chlorine, and fluorine atoms.

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30
Q

What are Cl radicals?

A

Chlorine radicals are highly reactive chemical species that are formed when chlorofluorocarbons (CFCs) are exposed to ultraviolet (UV) radiation in the upper atmosphere. UV radiation breaks the C-Cl bonds in CFC molecules, releasing chlorine radicals.

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31
Q

What is the ozone layer?

A

The ozone layer is a natural layer of ozone (O3) located in the Earth’s upper atmosphere, specifically in the stratosphere. It plays a crucial role in protecting life on Earth by absorbing and filtering out a significant portion of the sun’s ultraviolet (UV) radiation.

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32
Q

What is smog?

A

Smog refers to a type of air pollution that is characterized by a mixture of pollutants, including ground-level ozone, particulate matter, nitrogen oxides, and volatile organic compounds. It is typically formed when pollutants emitted by human activities, such as vehicle emissions, industrial processes, and the burning of fossil fuels, react with sunlight.

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33
Q

What is ozone depletion?

A

Ozone depletion refers to the process by which the ozone layer in the upper atmosphere is gradually depleted or thinned out. The ozone layer is a natural layer of ozone (O3) that acts as a protective shield, blocking harmful ultraviolet (UV) radiation from the sun.

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34
Q

What is ground level ozone?

A

Ground-level ozone, also known as tropospheric ozone, refers to ozone (O3) present in the lower atmosphere, closer to the Earth’s surface. Unlike the ozone layer in the upper atmosphere, ground-level ozone is a pollutant and a component of smog.

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35
Q

What caused a gap in the ozone layer?

A

Chlorofluorocarbons (CFCs) caused a gap in the ozone layer.

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36
Q

How can CFCs react with ozone?

A

CFCs can split up and form chlorine radicals that react with ozone.

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37
Q

What role do chlorine radicals play in the decomposition of ozone?

A

Chlorine radicals catalyse the decomposition of ozone and continue to be regenerated.

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38
Q

What was the stance of chemists regarding CFCs?

A

Chemists supported banning CFCs and using safer alternatives like HFCs.

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39
Q

What is the contribution of ozone in the lower atmosphere?

A

Ozone in the lower atmosphere contributes to smog formation.

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40
Q

How does the application of CFCs lead to the depletion of the ozone layer?

A

CFCs break down into chlorine radicals under UV radiation, which then react with ozone molecules, leading to the depletion of the ozone layer.

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41
Q

How many ozone molecules can one chlorine radical destroy in a chain reaction?

A

One chlorine radical can destroy two ozone molecules in a chain reaction.

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42
Q

What makes HFCs a safer alternative to CFCs?

A

HFCs have stronger bonds and are not affected by UV radiation.

43
Q

What is an addition reaction?

A

An addition reaction is a reaction where two molecules combine to form one. In the context of alkenes, addition reactions occur when electrophiles react with the double bond, resulting in the addition of atoms or groups to the alkene.

44
Q

What is Markovnikov’s Rule?

A

Markovnikov’s Rule states that in most cases, when an unsymmetrical alkene reacts with an electrophile, the electrophile will add to the carbon atom with the fewest attached hydrogens. This rule is based on the stability of the resulting carbocation intermediate.

45
Q

What is a carbocation?

A

A carbocation is an intermediate species formed during electrophilic addition reactions of alkenes. It is a positively charged carbon atom that is formed when the double bond’s electrons repel the electron pair in the electrophile’s bond.

46
Q

What is hydration?

A

Hydration is a chemical process in which alkenes are directly converted to alcohols by reacting them with water in the presence of an acid catalyst. This process is commonly used in industrial settings to produce alcohols from alkenes.

47
Q

What is a C-C sigma bond?

A

A C-C sigma bond is a covalent bond formed between two carbon atoms in an alkene. It is a single bond that allows rotation around the carbon-carbon axis.

48
Q

What is polymerisation?

A

Polymerisation is a process in which small molecules called monomers are chemically bonded together to form a larger molecule called a polymer. Addition polymerisation is a type of polymerisation that occurs with alkenes, where the double bond is broken and new bonds are formed to create a long chain polymer.

49
Q

What is plasticiser?

A

A plasticiser is a substance added to a polymer to increase its flexibility and reduce its rigidity. It weakens the intermolecular forces between polymer chains, allowing them to move more freely.

50
Q

What is a C=C pi bond?

A

A C=C pi bond is a covalent bond formed between two carbon atoms in an alkene. It is a double bond that restricts rotation around the carbon-carbon axis.

51
Q

What are alkenes?

A

Alkenes are a type of unsaturated hydrocarbon with the general formula CnH2n. They have a carbon-carbon double bond somewhere in their structure.

52
Q

What is a poly(alkene)?

A

Poly(alkene) is a polymer formed through addition polymerisation of alkenes. It consists of repeating units of the alkene monomer.

53
Q

What type of reactions do alkenes undergo with electrophiles?

A

Alkenes undergo addition reactions with electrophiles.

54
Q

What is the basis for the addition of bromine in the reaction of hydrogen bromide with alkenes?

A

The addition of HBr follows Markovnikov’s rule, where bromine adds to the carbon with the fewest attached hydrogens.

55
Q

What happens when a Br2 molecule approaches an alkene?

A

The pi bond’s electrons repel the electron pair in the Br-Br bond, creating a temporary polarity with Br2 becoming electrophilic.

56
Q

How can alkenes be directly converted to alcohols in an industrial setting?

A

Industrially, alkenes can be directly converted to alcohols by reacting them with water in the presence of an acid catalyst.

57
Q

What is the role of sulfuric acid in the conversion of alkenes to alcohols?

A

Sulfuric acid acts as a catalyst in the conversion of alkenes to alcohols.

58
Q

What is the purpose of the hydration process?

A

The purpose of the hydration process is to convert alkenes into alcohols. It is preferred in industries due to its high atom economy and lack of waste products.

59
Q

What is the general formula for alkenes and what is their defining feature?

A

Alkenes are unsaturated hydrocarbons with the general formula CnH2n and they have a carbon-carbon double bond.

60
Q

How can alkenes be converted to alkyl hydrogen sulfate?

A

Alkenes can be converted to alkyl hydrogen sulfate using concentrated sulfuric acid.

61
Q

What are the essential conditions for carrying out the hydration process?

A

The essential conditions for carrying out the hydration process are a high temperature of 300°C to 600°C, a high pressure of 70 atm, and the catalyst being concentrated H3PO4.

62
Q

How can bromine water be used to detect the presence of double bonds in alkenes?

A

Bromine water can be used as a test to detect the presence of double bonds in alkenes. It loses its color in the presence of a double bond.

63
Q

What is ethanol?

A

Ethanol is a type of alcohol with the chemical formula C2H5OH. It is a clear, colorless liquid that is commonly used as a solvent, fuel, and beverage.

64
Q

What is fractional distillation?

A

Fractional distillation is a separation technique used to separate a mixture of liquids with different boiling points. It involves heating the mixture and collecting the vapors that are produced.

65
Q

What is maltose?

A

Maltose is a disaccharide composed of two glucose units linked together. It is formed by the breakdown of starch in the presence of enzymes, such as amylase.

66
Q

What is yeast?

A

Yeast is a type of microorganism that belongs to the fungus kingdom. It is widely used in the production of alcoholic beverages, bread, and other fermented foods.

67
Q

What happens when you react alcohols with sodium?

A

Reacting alcohols with sodium is a chemical reaction in which an alcohol reacts with sodium metal to produce an alkoxide and hydrogen gas. When a small piece of sodium is added to an alcohol, it reacts vigorously, releasing bubbles of hydrogen gas.

68
Q

What is the preparation of alcohols?

A

Preparation of alcohols refers to the methods and processes used to synthesize alcohols from different starting materials. These methods can involve chemical reactions, such as reduction of aldehydes or ketones, hydration of alkenes, or fermentation of sugars.

69
Q

What is the dehydration of alcohols?

A

Dehydration of alcohols using an acid catalyst is a chemical reaction in which an alcohol is converted into an alkene by removing a molecule of water. This reaction is commonly used in organic chemistry to synthesize alkenes from alcohols.

70
Q

What is the dehydration of ethanol to produce ethene?

A

Dehydrating ethanol to produce ethene is a chemical reaction in which ethanol is converted into ethene by removing a molecule of water. This reaction is commonly used to produce gaseous alkenes, specifically ethene, for various applications.

71
Q

What is acid-catalysed hydration using conc.H2SO4?

A

Acid-catalysed hydration using concentrated sulphuric acid is a chemical reaction used to convert alkenes into alcohols. In this reaction, the alkene is treated with concentrated sulphuric acid (H2SO4) as a catalyst and water (H2O).

72
Q

What is the dehydration of cyclohexanol to obtain cyclohexene?

A

Dehydration of cyclohexanol to obtain cyclohexene is a chemical reaction in which cyclohexanol is converted into cyclohexene by removing a molecule of water. This reaction is commonly used to demonstrate the creation and purification of a liquid product in organic chemistry.

73
Q

What is direct hydration?

A

Direct hydration is a chemical reaction used to produce alcohols, such as ethanol, directly from their corresponding alkenes. In this reaction, the alkene is reacted with water (H2O) in the presence of a catalyst, such as phosphoric acid.

74
Q

What is reflux?

A

Reflux is a laboratory technique used in organic chemistry to carry out reactions under controlled conditions. It involves heating a reaction mixture in a flask and continuously condensing and returning the vapors that are produced back into the flask.

75
Q

What is reduction with NaBH4?

A

Reduction with sodium tetrahydridoborate(lll) (NaBH4) is a chemical reaction commonly used in organic chemistry to convert aldehydes and ketones into their corresponding alcohols. NaBH4 is a mild reducing agent that selectively reduces the carbonyl group of aldehydes and ketones, while leaving other functional groups intact.

76
Q

What is fermentation?

A

Fermentation is a metabolic process in which microorganisms, such as yeast or bacteria, convert sugars into alcohol, acids, or gases. It is an anaerobic process, meaning it occurs in the absence of oxygen.

77
Q

What is the dehydration of complex alcohols?

A

Dehydrating more complex alcohols refers to the process of converting alcohols with multiple carbon atoms into alkenes by removing a molecule of water. This process can be challenging due to the potential formation of multiple alkenes.

78
Q

What is alcohol production?

A

Alcohol production refers to the process of synthesizing alcohols, such as ethanol, from various starting materials. There are different methods for alcohol production, including chemical reactions and fermentation.

79
Q

What are the resulting substances of the dehydration of butan-2-ol?

A

The resulting substances are but-1-ene, cis-but-2-ene, and trans-but-2-ene.

80
Q

What is an alternative method of ethanol production from hydrating alkenes?

A

An alternative method of ethanol production is through fermentation, where starchy plant materials are broken down into simpler carbohydrates, transformed into glucose and fructose by yeast enzymes, and then into ethanol and carbon dioxide.

81
Q

Why is caution necessary when dealing with more complex alcohols in the dehydration process?

A

When dealing with more complex alcohols, caution is necessary due to the potential formation of multiple alkenes.

82
Q

What are the products formed when alcohols react with sodium?

A

Reacting alcohols with sodium produces alkoxides and hydrogen gas.

83
Q

What is the purity of ethanol obtained through fractional distillation?

A

Fractional distillation yields 96% pure ethanol, with the remaining 4% being water that cannot be removed through distillation.

84
Q

What catalyst is used in the dehydration of cyclohexanol to obtain cyclohexene?

A

The dehydration of cyclohexanol to obtain cyclohexene can be demonstrated using concentrated phosphoric(V) acid as a catalyst.

85
Q

How is ethanol produced through direct hydration of ethene?

A

Ethanol can also be produced through direct hydration of ethene using a catalyst, phosphoric acid, at high temperature and pressure.

86
Q

How is ethanol produced through fermentation?

A

Ethanol can be produced through fermentation using glucose from the hydrolysis of starch and yeast under specific conditions.

87
Q

Why is phosphoric(V) acid preferred over sulfuric acid in the dehydration of cyclohexanol to obtain cyclohexene?

A

Phosphoric(V) acid is preferred over sulfuric acid due to its safer nature and cleaner reaction. Unlike sulfuric acid, phosphoric(V) acid is not a strong oxidizing agent.

88
Q

How many distinct alkenes are formed upon the dehydration of butan-2-ol?

A

Butan-2-ol yields three distinct alkenes upon dehydration.

89
Q

How is ethanol produced from ethene?

A

Ethanol can be produced from ethene through a reversible reaction using a solid silicon dioxide catalyst coated with phosphoric(V) acid, with only 5% of ethene turning into ethanol in one reactor pass but achieving a total conversion of 95% by reusing the remaining ethene.

90
Q

What is a primary alcohol?

A

A primary alcohol is an alcohol in which the carbon atom adjacent to the hydroxyl group is connected to one other carbon atom.

91
Q

What is oxidation?

A

Oxidation is a chemical reaction in which a substance loses electrons, resulting in an increase in its oxidation state. In the context of alcohols, oxidation refers to the process of converting an alcohol into a different compound by removing hydrogen atoms or adding oxygen atoms.

92
Q

What is reflux?

A

Reflux is a technique used in chemistry to heat a reaction mixture and condense any volatile components that evaporate, allowing them to return to the reaction vessel. In the context of alcohol oxidation, reflux is often used to prevent the intermediate aldehyde from undergoing further oxidation.

93
Q

What is a secondary alcohol?

A

A secondary alcohol is an alcohol in which the carbon atom adjacent to the hydroxyl group is connected to two other carbon atoms.

94
Q

What is an oxidising agent?

A

An oxidising agent is a substance that causes oxidation by accepting electrons from another substance. In the context of alcohol oxidation, a common oxidising agent is a solution of sodium or potassium dichromate(VI) made acidic with dilute sulfuric acid.

95
Q

What are alcohols?

A

Alcohols are organic compounds that contain a hydroxyl (-OH) functional group attached to a carbon atom. They can be classified as primary, secondary, or tertiary based on the number of carbon atoms connected to the carbon atom adjacent to the hydroxyl group.

96
Q

What is a tertiary alcohol?

A

A tertiary alcohol is an alcohol in which the carbon atom adjacent to the hydroxyl group is connected to three other carbon atoms.

97
Q

Why can’t tertiary alcohols undergo oxidation?

A

Tertiary alcohols lack a hydrogen atom connected to the carbon, so these specific hydrogen atoms cannot be eliminated to form the carbon-oxygen double bond.

98
Q

What do the simplified equations illustrate?

A

The simplified equations illustrate the connection between the alcohol and the resulting product.

99
Q

How can alcohols be classified?

A

Alcohols can be classified as primary, secondary, and tertiary based on the number of carbon atoms connected to the carbon atom adjacent to the oxygen.

100
Q

How are secondary alcohols converted through oxidation?

A

Secondary alcohols are directly converted to ketones through oxidation.

101
Q

How can an aldehyde be obtained from an alcohol?

A

To obtain an aldehyde, an excess of the alcohol is used, and the aldehyde is immediately distilled off once it’s generated.

102
Q

What is the process of oxidation of alcohols?

A

Oxidation of alcohols involves the conversion of primary alcohols to aldehydes and then to carboxylic acids using an oxidising agent.

103
Q

What are the requirements for the oxidation reaction?

A

The reaction requires a large amount of the oxidising agent and the intermediate aldehyde must be kept in the mixture.