Question

(a) Henry’s law is related to solubility of a gas in liquid.

(i) State Henry’s law.

(ii) Write any two applications of Henry’s law.

(b) 1000cm³ of an aqueous solution of a protein contains 1.26 gm of the protein. The osmotic pressure of such a solution at 300 K is found to be 2.57 x 10^-3 bar. Calculate molar mass of the protein. (R = 0.083 L bar mol^-1 K^-1)

Answer 1

(a) 

(i) Henry’s law states that at constant tempera-ture, the solubility of a gas in a liquid is directly proportional to the pressure of the gas. p = K_H x where, p is the partial pressure of the gas in vapour phase, K_H is the Henry’s law constant and x is the mole fraction of the gas in the solution.

(ii) 1. To increase the solubility of CO₂ in soft drinks and soda water, the bottle is sealed under high pressure.

2. To avoid bends and the toxic effects of high concenration of nitrogen in blood, the tanks used by scuba divers are filled with air diluted with helium.

3. Low partial pressure of oxygen at high altitudes leads to low concentration of oxygen in the blood and tissues of people living at high altitudes or climbers and causes anoxia.