UNIT#04 LIQUIDS Flashcards

1
Q

CHCl3 exist in a liquid state due to;

A

Dipole-Dipole Forces

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2
Q

The highest boiling point among the following is for:

A

Br2
(Intermolecular Force⬆ Vapour Pressure⬇ Boiling Point⬆)
➡has a stronger London Dispersion force due to molar mass

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3
Q

In NH3, dominant Van der Waal’s force among the following is:

A

Hydrogen Bonding

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4
Q

Liquids have no definite shape; it is because:

A

The molecules of the liquid are in constant motion by sliding over each other

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5
Q

Propanone is miscible in water due to:

A

➡Both are polar molecules
➡Hydrogen bonding between them
➡Dipole-Dipole attraction between them

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6
Q

Strong dipole-dipole forces among the liquid molecules are responsible for:

A

The very high heat of vaporization

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7
Q

Which one of the following arrangements usually represents the correct order of increasing interactions?

A

London Forces, Dipole-Dipole, Hydrogen Bonding

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8
Q

Which of the following has the strongest intermolecular forces of attraction

A

Iodine
(Molar mass⬆ Polarizability⬆ London Dispersion Force)

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9
Q

The forces which are present between the ions and water molecules are known as:

A

Ion dipole forces

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10
Q

Forces of attraction, which may be present between all kinds of atoms and molecules are:

A

London Dispersion forces

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11
Q

The attractive forces between the partially positive end of one molecule and the partial negative end of another molecule are called:

A

Dipole-Dipole forces

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12
Q

Liquid gets the shape of the container when it is poured into it. Which one of the following reasons justifies it

A

The liquid does not have a definite shape

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13
Q

The nature of bonding affects the properties like:

A

➡Solubility
➡Melting, Boiling Points and isomerism
➡Reaction Kinetics

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14
Q

The Vapour pressure of water is 4.579 torr and 9.209 torrs at 10° C, so the increase in vapour pressure from 0° C to 10° C is 4.630 torr. What will be the change in vapour pressure from 90° C to 100° C?

A

> 4.630 torr

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15
Q

Which of the following has the highest vapour pressure?

A

Iso-pentane➡has the weakest force of attraction
(V.P α 1/ Intermolecular Force)

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16
Q

The boiling point of water would be highest at:

A

Gawadar

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17
Q

Which one is false for evaporation:

A

Exothermic
(Evaporation is an endothermic process)

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18
Q

Vapour pressure of water at 100° C is:

A

760 mm Hg

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19
Q

The conversion of vapours back into other liquid states is called:

A

Condensation

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20
Q

Which one of the following has the highest volatility

A

Diethyl Ether
(L.D.F⬆ V.P⬇ Volatility⬆)

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21
Q

In order to mention the boiling point of water at 110° C, the external pressure should be:

A

Between 760 torr and 1200 torr
(Boiling point of liquid α External Pressure

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22
Q

The boiling point increases down the zero group element due to:

A

London Forces

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23
Q

If we provide a very high amount of heat to a liquid its boiling point will:

A

Remain constant

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24
Q

Evaporation is designated as a colling process because of the reason:

A

High energy molecules leave behind the low energy molecules and cause cooling

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25
Q

The Vapour pressure of a liquid depends upon the following:

A

Temperature and the inter-molecular forces
(➡V.P α Temperature
➡ V.P α 1/ Intermolecular Forces)

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26
Q

At 1atm pressure, liquid 1 has the boiling point less than liquid 2, what can we predict about both the liquids?

A

➡Liquid 1 has high vapour pressure than the liquid 2
➡Liquid 1 has a weak intermolecular force of attraction than the liquid 2
➡Liquid 1 is more volatile than the liquid 2

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27
Q

The distillation of a solution under reduced pressure is called:

A

Vacuum Distillation

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28
Q

A pressure cooker reduces cooking time because:

A

The boiling point of water rises

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29
Q

Molar heat of vaporization of water is:

A

➡40.6 kJ/mol

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30
Q

The rate of evaporation of a liquid depends upon:

A

➡Surface area of liquid
➡Temperature
➡Intermolecular Forces

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31
Q

Which one of the following would cause severe burning

A

Steam at 100° C

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32
Q

The boiling point of a liquid is the temperature at which

A

The vapour pressure of the liquid is equal to the atmospheric pressure

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33
Q

The strength of hydrogen bonding is:

A

20 times less than a covalent bond

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34
Q

When ammonia is dissolved in water, a number of hydrogen bonds formed with ammonia

A

1
(as there is one lone pair)

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35
Q

Lower alcohols are soluble in water because:

A

Intermolecular Hydrogen bonding

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36
Q

The strongest H-bond is:

A

F—H

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37
Q

When two ice cubes are passed over each other, they unite to form one cube. This is due to:

A

Hydrogen Bond Formation

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38
Q

Which of the following can form hydrogen bonding among its molecules more prominently

A

CH3OH

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39
Q

Hydrogen bonding is involved in:

A

➡Solubility
➡Cleasnsing action of detergents
➡Biological molecules

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40
Q

When water freezes at 0° C its density decreases due to:

A

Empty space present in the structure of ice

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41
Q

The correct order of boiling point of the given liquids is:

A

H2O>HF>NH3>HCl

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42
Q

At 1489 mmHg, water will boil at:

A

120° C

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43
Q

Ice is less dense than water at:

A

0° C

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44
Q

In a crystal lattice of ice, each O-atom of the water molecule is attached to:

A

Four H-atom

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45
Q

What is the reason that the ice at 0° C occupies more volume than water:

A

Empty spaces

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46
Q

Water has maximum density at:

A

4° C

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47
Q

DNA molecule is double-stranded, in which two chains of DNA are twisted around each other by:

A

Hydrogen Bond

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48
Q

Which of the following substances exhibits hydrogen bonding?

A

NH3

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49
Q

In the ‘H-F’ bond electronegativity difference is 2.0. What is the type of this bond?

A

Polar covalent bond

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50
Q

The boiling point of water is higher than petrol because intermolecular forces in water are:

A

Stronger than petrol

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51
Q

Metallic conduction involves the relatively free movement of their _____ throughout the metallic lattice:

A

Electrons

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52
Q

Which type of force is present in gasoline?

A

London Dispersion forces

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53
Q

Which one of the following hydrogen bonds is stronger than the other?

A

F-H——F-H

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54
Q

An intermolecular force of attraction X is relatively stronger than the other intermolecular forces, it stabilizes α-helix and β-pleated sheets of proteins. The double helical structure of DNA is also stabilized by this force of attraction. Identify X

A

Hydrogen Bonding

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55
Q

At higher altitudes, the boiling point of water is less than 100° C, this is because of:

A

Lower atmospheric pressure

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56
Q

Steam causes more severe burns than boiling water. It is due to:

A

High Latent Heat of vaporization

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57
Q

According to Watson and Crick’s model of DNA, the DNA molecule consists of the double helix. What type of forces is responsible to keep two strands of DNA together?

A

Hydrogen Bonding

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58
Q

CO2 and SO2 both are tri-atomic molecules but the heat of vaporization of SO2 is greater than that of CO2 due to:

A

SO2 is polar and CO2 is non-polar

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59
Q

Which of the following has the lowest vapour pressure at 20° C?

A

Water

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60
Q

Which of the following is not a molecular solid?

A

Bromine

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61
Q

The distillation which is carried out under reduced pressure is called as

A

Vaccum Distillation

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62
Q

In which of the following water evaporate earlier

A

Sauce pan

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63
Q

Conversion of water into steam is a

A

Spontaneous reaction

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64
Q

On which factors the vapour pressure of a substance does not depend

A

Surface Area

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65
Q

How many times of covalent bond is stronger than hydrogen bond

A

20 times

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66
Q

Separation of components of liquid on the basis of their boiling point called as

A

Fractional Distillation

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67
Q

Which instrument is used to measure the vapour pressure of a liquid

A

Manometer

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68
Q

Which of the following has highest vapour pressure

A

Diethyl ether

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69
Q

When heat provided to a liquid it causes it to

A

Expand

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70
Q

Which of the following intermolecular forces are present between Octane molecule

A

London Dispersion froces

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71
Q

Which of the following forces ability to form strong bonds

A

H-bond

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72
Q

At zero degree centigrade what is the physical state of water

A

Both ice and liquid

73
Q

Steam cause more advanced than boiling water because it has:

A

Latent heat of vaporization

74
Q

Hydrogen bonding is involved in

A

➡Biological molecules
➡Cleansing action of soap
➡Solubility

75
Q

In vacuum distillation the boiling point of glycerine is reduced to

A

210° C

76
Q

Hydrogen bonding is stronger than

A

➡Dipole Dipole Forces
➡London Forces
➡Debye Forces

77
Q

While calculating vapour pressure of a liquid in manometer the column of mercury facing the vapours of a liquid is ___ due to pressure on surface of liquids in flask:

A

Depressed

78
Q

The measurement of the extent to which electron cloud is distorted is termed as

A

Polarizability

79
Q

Molecules of liquids are in a constant state of motion it causes

A

➡Diffusion
➡Evaporation

80
Q

In the formation of HF,_____ donates the measure of its electron among hydrogen atom of chlorine atom

A

Boiling Point

81
Q

HF has high boiling point than HCl is:

A

Hydrogen Bonding

82
Q

The molecules of ___ have dipole-dipole interaction

A

Ammonia

83
Q

Hydrogen bonding is maximum in

A

Water

84
Q

When two ice cubes are passed over Each Other they Unite to form 1 cube. This is due to

A

Hydrogen bond formation

85
Q

Rate of evaporation of a liquid does not depend on

A

External pressure

86
Q

Which one of the following would cause severe burning

A

Steam at 101°C

87
Q

Which of the following in liquid has lowest boiling point

A

CH3OH

88
Q

In which of the following of the pairs, debye forces exist

A

Argon and water💦

89
Q

Kerosene oil is liquid at room temperature due to

A

London dispersion forces

90
Q

The heat of vaporization of H2O, C2H5OH and CS2 are 40.6KJ/mol, 38.6 KJ/mol,28.6 KJ/mol. The order of decreasing intermolecular forces in these liquids is:

A

H2O > C2H5OH > CS2

91
Q

A substance that is soluble in water due to dipole-induced dipole force:

A

Kr
(Krypton is non-polar

92
Q

Naphthalene is soluble in carbon tetrachloride due to the force:

A

London Forces

93
Q

The polarizabilities of electrons mostly increase down the group due to the;

A

Increase in the number of shell

94
Q

London forces are more significant in:

A

Non-polar molecules

95
Q

Which of the following intermolecular forces may be present in molecular solids:

A

➡Dipole-Dipole Forces
➡Van der Waal’s Forces
➡Hydrogen Bonding

96
Q

Which of the following highest boiling point

A

n-hexane
(Boiling Point ∝ Polarizability ∝ Molecular Size)

97
Q

Molar heat of vaporization is the highest for:

A

Iodine
(Size of molecules ∝ Polarizability)

98
Q

Which pair shows Debye forces:

A

HCl and Ar
(➡HCl is a polar molecule
➡Ar is a non-polar)

99
Q

Value of gas constant “R” is ____ if unit is atm dm3 mol-1 K-1

A

0.0821

100
Q

Which gas show marked deviation rom ideal behaviour?

A

CO2

101
Q

Which statement about evaporation is incorrect?

A

It is exothermic process

102
Q

Vapour pressure of a liquid depends upon one of the following factors

A

Inter molecular forces

103
Q

Vapour pressure of liquid is measured when liquid and the vapours are in equilibirum it means that:

A

Rate of evaporation equal to the rate of condensation

104
Q

Vapour pressure of water at 100°C is:

A

760 mmHg

105
Q

The boiling point of water is maximum when external pressure is:

A

1489 torr

106
Q

Water can boil at;

A

➡25°C
➡100°C
➡120°C

107
Q

NH3 shows maximum boiling point among the hydrides of group VA element due to;

A

Enhanced electronegative character of nitrogen

108
Q

Moving from 4°C to 0°C, the density of H2O:

A

Decreases

109
Q

The H2O cannot make h-bonding with:

A

CH4

110
Q

Water has maximum density at:

A

4°C

111
Q

London dispersion forces are present in;

A

➡I2
➡H2
➡He

112
Q

The rate of vapourization of gasoline is faster than water due to:

A

Weak London Forces

113
Q

Which one of the following is a solid with lowest melting point:

A

I2

114
Q

The low acidic strength of HF molecule as compared to HCl is due to:

A

Hydrogen Bonding

115
Q

Which one of the following arrangements represents the correct order of increasing interactions:

A

London Forces, Dipole-Dipole, Hydrogen Bonding

116
Q

The inter-molecular attractive forces vary in the order;

A

Ether < Alcohol < Water

117
Q

Heat of vaporization is minimum for;

A

HCl

118
Q

If we provide very large amount of heat to a liquid, its vapor pressure at its boiling point:

A

Remains the same

119
Q

The vapor pressure of water at 0°C is:

A

4.8 torr

120
Q

The boiling point of H2O is greater than that of C2H5OH due to;

A

Numebr of H-bonds are greater in H2O than in C2H5OH

121
Q

A substance with maximum vapor pressure at 25°C

A

Diethyl ether

122
Q

During which process the particles come so close to each other that the empty spaces between them are minimum:

A

Condensation

123
Q

Steam causes more severe burn than the boiling water because it possesses:

A

Latent heat of vaporization

124
Q

At top of Everest water boils at 69°C the external pressure is:

A

323 torr

125
Q

The boiling point of water would be highest at:

A

Karachi

126
Q

Which gas is most soluble in water:

A

NH3
(Compounds making strong hydrogen bond)

127
Q

Which one among the following does not have the hydrogen bond?

A

Liquid HCl

128
Q

H2O has higher boiling point than H2S because;

A

Of intermolecular hydrogen bonding in liquid H2O

129
Q

DNA molecule is double stranded, in which two chains of DNA are twisted around each other by:

A

Hydrogen bonds

130
Q

Density of liquid water ___ if temperature decreases from 25°C to 0°C

A

First increases and then decreases

131
Q

Forces of attractions in liquids are:

A

➡Stronger than gases
➡Weaker than solids

132
Q

Rather than gases in liquid contain ____

A

Fix volume

133
Q

If we increase or decrease the amount of heat in a liquid, its boiling point will;

A

Remains constant

134
Q

Which is the correct order of boiling points?

A

H2O > HF > NH3 > CH4

135
Q

Evaporation of water depends upon the following;

A

➡Sruface area an intermolecular forces
➡Speed of the air above the liquid surface
➡Humidity of air

136
Q

110°C boiling point of water corresponds to the external pressure

A

Between 760 to 1200 torr

137
Q

The boiling point of a compound is mostly raised by;

A

Intermolecular Hydrogen bonding

138
Q

Which has a greater enthalpy of vapourizaton

A

I2

139
Q

Identity incorrect statement about evaporation;

A

➡Exothermic✅
➡Continuous❌
➡Cooling❌
➡Surface Phenomenon ❌

140
Q

Maximum vapour pressure is shown by:

A

➡50 cm^3 ethanol
➡1 dm^3 ethanol

141
Q

Evaporation occurs at:

A

All temperature

142
Q

Which one is the most accurate method for the measurement of vapour pressure

A

Manometric Method

143
Q

Vapour pressure of methanol at 40°C is less than;

A

Ether

144
Q

Ionic crystals are characterized by:

A

Solubility in Polar solvents

145
Q

NaCl crystal is;

A

Cubic

146
Q

Which element exists as a discrete small molecule in the solid state;

A

Iodine

147
Q

Ice floats on the liquid water because:

A

Water freezes at 0°C and is less dense than liquid water

148
Q

The density of an unknown gas ‘X’ is 1.98 g/dm^3 at STP. Unknown gas is:

A

CO2

149
Q

Which one of the following contains maximum hydrogen bonding?

A

H2O

150
Q

Ammonia shows the maximum boiling point because fo;

A

Enhanced electronegativity character of nitrogen

151
Q

The boiling point of H2O is 100°C while that of C2H5OH is 78.37°C. The reason is that:

A

The number of hydrogen bonds per H2O molecule is greater than C2H5Oh

152
Q

Which of the following in the liquid state has the lowest state boiling point?

A

CH3OH

153
Q

In which of the following pairs, do Debye forces exist:

A

➡Argon
➡Water

154
Q

Kerosene oil is liquid at room temperature due to:

A

London Dispersion forces

155
Q

Which of the following can form hydrogen bonding among its molecules more prominently

A

CH3OH

156
Q

Identify the incorrect statement about evaporation:

A

➡Continuous❌
➡Cooling❌
➡Exothermic✅
➡Surface❌

157
Q

Exceptionally low acidic strength of HF is due to;

A

Strong hydrogen Bonding

158
Q

In which of the following pairs, do Debye forces exist:

A

➡Argon
➡Water

159
Q

A pressure cooker reduces cooking time because;

A

The boiling point of water rises

160
Q

Hydrogen bonding is maximum in:

A

Water

161
Q

Molar heat of vaporization of water is;

A

40.6 kJ/mol

162
Q

The strongest H-bond is;

A

F—H

163
Q

Maximum vapour pressure is shown by:

A

➡1 dm^3 ethanol
➡50 cm^3 ethanol

164
Q

The Vapour pressure of a liquid depends upon the following;

A

Temperature and the inter-molecular forces

165
Q

At 1 atm pressure, liquid 1 has the boiling point less than liquid 2, what can we predict about both liquids

A

➡Liquid 1 has high vapour pressure than the liquid 2
➡Liquid 1 has a weak intermolecular force of attraction than the liquid 2
➡Liquid 1 is more volatile than the liquid 2

166
Q

The strength of hydrogen bonding is:

A

20 times less than a covalent bond

167
Q

110°C boiling point o water corresponds to the external pressure.

A

Between 760 torr to 1200 torr

168
Q

Lower alcohols are soluble in water because;

A

Intermolecular Hydrogen bonding

169
Q

Ammonia shows the maximum boiling point because o;

A

Enhanced electronegativity character of nitrogen

170
Q

Ice floats on the liquid water because:

A

Water freezes at 0°C and is less dense than liquid water

171
Q

Hydrogen bonding is extensively present in protein which forms the spiral. The hydrogen bond being produced is between;

A

➡Oxygen
➡Hydrogen

172
Q

Ice occupies more space than liquid water:

A

9%

173
Q

The boiling point of water is 100°C while that of C2H5Oh is 78.5°C. The reason is that :

A

The number of hydrogen bonds per H2O molecule is greater than C2H5OH

174
Q

The distillation of a solution under reduced pressure is called:

A

Vaccum Distillation

175
Q

Which liquid has the lowest vapour pressure

A

H2O

176
Q

The boiling point of a compound is mostly raised by:

A

Intermolecular Hydrogen Bonding

177
Q

Propanone is miscible in water due to;

A

➡Both are polar molecules
➡Dipole-Dipole attraction between them
➡Hydrgoen bonding between them

178
Q

Which has a greater enthalpy of vaporization;

A

I2