A 10% solution (by mass) of sucrose in water has the freezing point of 269.15 K.Calculate the freezing point of 10% glucose in water if freezing point of pure water is273.15 K.

Given : (Molar mass of sucrose = 342 g mol^–1) (Molar mass of glucose = 180 g mol^–1)

Write one difference in each of the following:
Solution and Colloid

Calculate the freezing point of a solution containing 60 g of glucose (Molar mass = 180 g mol–1) in 250 g of water.
(K_f of water = 1.86 K kg mol^–1)

Give reasons for the following :

Measurement of osmotic pressure method is preferred for the determination of molar masses of macromolecules such as proteins and polymers.

Give reasons for the following:

Aquatic animals are more comfortable in the cold water than in warm water.

276.

Give reasons for the following:

Elevation of the boiling point of 1 M KCl solution is nearly double than that of 1 M sugar solution.

18 g glucose ₍C₆H₁₂O₆ ) is added to 178.2 g water. The vapor pressure of water (in torr) for this aqueous solution is:

• 76.0

• 752.4

• 759.0

• 759.0

The vapour pressure of acetone at 20^oC is 185 torr. When 1.2 g of a non-volatile substance was dissolved in 100 g of acetone at 20^oC, its vapour pressure was 183 torr. The molar mass (g mol^-1 ) of the substance is:

• 32

• 64

• 128

• 128

3 g of activated charcoal was added to 50 mL of acetic acid solution (0.06N) in a flask. After an hour it was filtered and the strength of the filtrate was found to be 0.042 N. The amount of acetic acid adsorbed (per gram of charcoal) is:

• 18 mg

• 36 mg

• 42 mg

• 42 mg

For the estimation of nitrogen 1.4g of an organic compound was digested by Kjeldahl's method and the evolved ammonia was absorbed in 60 mL of M/10 sulphuric acid. The unreacted acid required 20 mL of M/10 sodium hydroxide for complete neutralisation. The percentage of nitrogen in the compound is 

• 6%

• 10%

• 3%

• 3%