KAPPA CLASSES – TEST SERIES 1

(A) increase
(B) decrease
(C) remain same
(D) first increase and then decrease

(A) 1% KCl
(B) 1% glucose
(C) 1% urea
(D) 1% CaCl₂

(A) greater for gases with higher solubility
(B) greater for gases with lower solubility
(C) constant for all gases
(D) not related to the solubility of gases

(A) 1.0 M KCl
(B) 1.0 M Na₂SO₄
(C) 1.0 M Glucose
(D) 1.0 M AlCl₃

(A) −3.72°C
(B) +3.72°C
(C) −1.86°C
(D) +2.72°C

(A) obeys Raoult’s law
(B) forms an ideal solution
(C) shows a positive deviation from Raoult’s law
(D) shows a negative deviation from Raoult’s law

(A) it gains water due to osmosis
(B) it loses water due to reverse osmosis
(C) it gains water due to reverse osmosis
(D) it loses water due to osmosis

Assertion (A): Cooking time is reduced in pressure cooker.
Reason (R): Boiling point of water inside the pressure cooker is elevated.

Assertion (A): Henry’s law constant decreases with increase in temperature.
Reason (R): As the temperature increases, solubility of gases in liquids decreases.

Assertion (A): The boiling point of ethanol is higher than that of methoxymethane.
Reason (R): There is intramolecular hydrogen bonding in ethanol.

(a) Cooking is faster in pressure cooker than in an open pan.
(b) On mixing liquid X and liquid Y, volume of the resulting solution decreases.

What type of deviation from Raoult’s law is shown by the resulting solution?
What change in temperature would you observe after mixing liquids X and Y?

Define azeotrope. What type of azeotrope is formed by negative deviation from Raoult’s law? Give an example.

What is meant by positive deviation from Raoult’s law? Give an example.
What type of azeotrope is formed by positive deviation?

Calculate the elevation of boiling point of a solution when 3 g of CaCl₂ (Molar mass = 111 g mol⁻¹) was dissolved in 260 g of water, assuming complete dissociation.

Liquids ‘X’ and ‘Y’ form an ideal solution. The vapour pressure of pure ‘X’ and pure ‘Y’ are 120 mm Hg and 160 mm Hg respectively. Calculate the vapour pressure of the solution containing equal moles of ‘X’ and ‘Y’.

State Henry’s law. Why are aquatic species more comfortable in cold water as compared to warm water?

A solution of glucose (molar mass = 180 g mol⁻¹) in water has a boiling point of 100.20°C. Calculate the freezing point of the same solution.

At 25°C the saturated vapour pressure of water is 24 mm Hg. Find the saturated vapour pressure of a 5% aqueous solution of urea at the same temperature. (Molar mass of urea = 60 g mol⁻¹)

0.3 g of acetic acid (molar mass = 60 g mol⁻¹) dissolved in 30 g of benzene shows a depression in freezing point equal to 0.45°C. Calculate the percentage association of acid if it forms a dimer in the solution.

Vapour pressure of pure water at 298 K is 24.8 mm Hg. Calculate the lowering in vapour pressure of an aqueous solution which freezes at −0.3°C.

Shweta mixed two liquids A and B of 10 mL each. After mixing, the volume of the solution was found to be 20.2 mL.
(i) Why was there a volume change after mixing the liquids?
(ii) Will there be an increase or decrease of temperature after mixing?
(iii) Give one example for this type of solution.

(i) How does sprinkling of salt help in clearing snow-covered roads in hilly areas?
(ii) What happens when red blood cells are kept in 0.5% (mass/vol) NaCl solution? Justify your answer.
(iii) Write an application of reverse osmosis.

According to the generally accepted definition of the ideal solution there are equal interaction forces acting between molecules belonging to the same or different species. (This is equivalent to the statement that the activity of the components equals the concentration.) Strictly speaking, this condition is fulfilled only in exceptional cases for mixtures (optical isomers, isotopic mixtures of an element, hydrocarbon mixtures). It is still usual to talk about ideal solutions as limiting cases in reality since very dilute solutions behave ideally with respect to the solvent. This view is further supported by the fact that Raoult’s law empirically found for describing the behaviour of the solvent in dilute solutions can be deduced thermodynamically via the assumption of ideal behaviour of the solvent.

Answer the following questions:

(a) Give one example of a miscible liquid pair which shows negative deviation from Raoult’s law. What is the reason for such deviation?

(b) (i) State Raoult’s law for a solution containing volatile components.

OR

(ii) Raoult’s law is a special case of Henry’s law. Comment.

(c) Write two characteristics of an ideal solution.