Solutions — Class 12 Chemistry PYQs

For an electrolyte undergoing association in a solvent, the van't Hoff factor :
(A) is always greater than one
(B) has negative value
(C) has zero value
(D) is always less than one

The system that forms maximum boiling azeotrope is :
(A) CS₂ and acetone
(B) Benzene and toluene
(C) Ethanol and acetone
(D) Chloroform and acetone

Phenol dimerises in benzene having van't Hoff factor 0.54. Its degree of association is :
(A) 0.54
(B) 0.46
(C) 0.92
(D) 0.27

An azeotropic solution of two liquids has boiling point higher than either of them when it :
(A) is saturated
(B) shows positive deviation from Raoult’s law
(C) shows negative deviation from Raoult’s law
(D) shows no deviation from Raoult’s law

An azeotropic solution of two liquids has boiling point lower than either of them when it :
(A) is saturated
(B) shows positive deviation from Raoult’s law
(C) shows negative deviation from Raoult’s law
(D) shows no deviation from Raoult’s law

On mixing 10 mL of acetone with 50 mL of chloroform, the total volume of the solution will be :
(A) < 60 mL
(B) > 60 mL
(C) = 60 mL
(D) = 100 mL

The relative lowering of vapour pressure of an aqueous solution containing non-volatile solute is 0.0225. The mole fraction of the non-volatile solute is :
(A) 0.80
(B) 0.725
(C) 0.15
(D) 0.0225

Assertion (A) : When NaCl is added to water a depression in freezing point is observed.
Reason (R) : NaCl undergoes dissociation in water.
(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
(C) Assertion (A) is true, but Reason (R) is false.
(D) Assertion (A) is false, but Reason (R) is true.

Assertion (A) : ΔmixH for an ideal solution is not equal to zero.
Reason (R) : A – B interactions in an ideal solution are same as between A – A and B – B interactions.
(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
(C) Assertion (A) is true, but Reason (R) is false.
(D) Assertion (A) is false, but Reason (R) is true.

Assertion (A) : When NaCl is added in water, elevation in boiling point is observed.
Reason (R) : Elevation in boiling point is a colligative property.
(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
(C) Assertion (A) is true, but Reason (R) is false.
(D) Assertion (A) is false, but Reason (R) is true.