Colligative Properties of Dilute Solutions (a Relative Lowering of Vapour Pressure, Depression of Freezing Point...) NEET Questions

Physical Chemistry - Solutions

Colligative Properties of Dilute Solutions (a Relative Lowering of Vapour Pressure, Depression of Freezing Point...) MCQ Questions


13.
Kb (molal elevation constant) for a solvent depends on:
A.
Nature of the solute only
B.
Mass of the solute
C.
Nature of the solvent (its molar mass, boiling point, and enthalpy of vapourisation)
D.
Mass of the solvent
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ANSWER :
C. Nature of the solvent (its molar mass, boiling point, and enthalpy of vapourisation)
14.
Kb for water is 0.52 K kg mol⁻¹. The boiling point elevation when 18 g of glucose (M = 180 g/mol) is dissolved in 1 kg of water is:
A.
5.2 K
B.
0.52 K
C.
0.052°C above 100°C
D.
0.052 K
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ANSWER :
D. 0.052 K
15.
When a non-volatile solute is added to a volatile solvent, the boiling point of the solution:
A.
Remains the same
B.
Decreases compared to pure solvent
C.
Increases compared to pure solvent
D.
First increases, then decreases
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ANSWER :
C. Increases compared to pure solvent
16.
1.80 g of a non-volatile solute when dissolved in 90 g of benzene raises the boiling point by 0.88 K. If Kb of benzene = 2.53 K kg mol⁻¹, the molar mass of the solute is:
A.
29 g mol⁻¹
B.
116 g mol⁻¹
C.
58 g mol⁻¹
D.
180 g mol⁻¹
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ANSWER :
C. 58 g mol⁻¹
17.
The molal elevation constant Kb is defined as the elevation of boiling point when:
A.
1 mole of solute is dissolved in 1 mole of solvent
B.
1 mole of solute is dissolved in 1 L of solvent
C.
1 g of solute is dissolved in 1 kg of solvent
D.
1 mole of solute is dissolved in 1 kg of solvent (1 molal solution)
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ANSWER :
D. 1 mole of solute is dissolved in 1 kg of solvent (1 molal solution)
18.
Among the following solvents, which one has the highest Kb value?
A.
Water (Kb = 0.52)
B.
Ethanol (Kb = 1.20)
C.
Benzene (Kb = 2.53)
D.
Carbon tetrachloride (Kb = 5.03)
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ANSWER :
D. Carbon tetrachloride (Kb = 5.03)