Chemistry 12 Chapter 2 Exemplar Solutions Question and Answer Part 2

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Question 7:

Considering the formation, breaking and strength of hydrogen bond, predict which of the following mixtures will show a positive deviation from Raoult’s law?

(i) Methanol and acetone.

(ii) Chloroform and acetone.

(iii) Nitric acid and water.

(iv) Phenol and aniline.

Answer: (i)

Question 8:

Colligative properties depend on ____________.

(i) The nature of the solute particles dissolved in solution.

(ii) The number of solute particles in solution.

(iii) The physical properties of the solute particles dissolved in solution.

(iv) The nature of solvent particles.

Answer (ii)

Question 9:

Which of the following aqueous solutions should have the highest boiling point?

(i)

(ii)

(iii)

(iv)

Answer: (ii)

Question 10:

The unit of ebulioscopic constant is _______________.

(i)

(ii)

(iii)

(iv)

Answer: (iii)

Question 12:

An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because _____________.

(i) It gains water due to osmosis.

(ii) It loses water due to reverse osmosis.

(iii) It gains water due to reverse osmosis.

(iv) It loses water due to osmosis.

Answer: (iv)

Question 13:

At a given temperature, osmotic pressure of a concentrated solution of a substance _____________.

(i) Is higher than that at a dilute solution.

(ii) Is lower than that of a dilute solution.

(iii) Is same as that of a dilute solution.

(iv) Cannot be compared with osmotic pressure of dilute solution.

Answer: (i)

Question 14:

Which of the following statements is false?

(i) Two different solutions of sucrose of same molality prepared in different solvents will have the same depression in freezing point.

(ii) The osmotic pressure of a solution is given by the equation (where is the molarity of the solution).

(iii) Decreasing order of osmotic pressure for aqueous solutions of barium chloride, potassium chloride, acetic acid and sucrose is sucrose.

(iv) According to Raoult’s law, the vapour pressure exerted by a volatile component of a solution is directly proportional to its mole fraction in the solution.

Answer: (i)

Question 15:

The values of Hoff factors for , and , respectively, are _____________.

(i) 2, 2 and 2

(ii) 2, 2 and 3

(iii) 1, 1 and 2

(iv) 1, 1 and 1

Answer: (ii)

Question 16:

Which of the following statements is false?

(i) Units of atmospheric pressure and osmotic pressure are the same.

(ii) In reverse osmosis, solvent molecules move through a semipermeable membrane from a region of lower concentration of solute to a region of higher concentration.

(iii) The value of molal depression constant depends on nature of solvent.

(iv) Relative lowering of vapour pressure, is a dimensionless quantity.

Answer: (ii)

Question 17:

Value of Henry’s constant ____________.

(i) Increases with increase in temperature.

(ii) Decreases with increase in temperature.

(iii) Remains constant.

(iv) First increases then decreases.

Answer: (i)

Question 18:

The value of Henry’s constant is _____________.

(i) Greater for gases with higher solubility.

(ii) Greater for gases with lower solubility.

(iii) Constant for all gases.

(iv) Not related to the solubility of gases.

Answer: (ii)

Question 19:

Consider the Fig. 2.1 and mark the correct option.

(i) Water will move from side (A) to side (B) if a pressure lower than osmotic pressure is applied on piston (B).

(ii) Water will move from side (B) to side (A) if a pressure greater than osmotic pressure is applied on piston (B).

(iii) Water will move from side (B) to side (A) if a pressure equal to osmotic pressure is applied on piston (B).

(iv) Water will move from side (A) to side (B) if pressure equal to osmotic pressure is applied on piston (A).

Pressure equal to osmotic pressure

Pressure Equal to Osmotic Pressure

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Fig. 2.1

Answer: (ii)