Question:

A gas ‘X’ when dissolved in water, heat is evolved. Then solubility of ‘X’ will increase at:

a) Low pressure, high temperature

b) Low pressure, low temperature

c) high pressure, high temperature

d) High pressure, low temperature

Solution:

X(g)+ "water"<=> X(aq)+ "heat"

This is exothermic reaction. Exothermic reactions are favored at low temperature according to Lechatelier's principle.

Since there is a decrese in volume in forward direction, it will be favoured at high pressure.

Therefore, option (d) is correct.