Question
Applying Le-Chatelier’s principle, predict the effect of temperature and pressure on the solubility of gas.
Solution
Dissolution of gas is an exothermic process. The equilibrium may be represented as:
Gas + Solvent
Solution; 
According to Le-Chatelier's principle:
(i) With the increase of temperature, the equilibrium shifts towards that direction where absorption of heat takes place in order to nullify the effect of the rising in temperature. In such case, the equilibrium will shift in the backward direction i.e., the solubility decreases.
(ii) With the increase of pressure, the volume is reduced. Consequently, the system proceeds in a direction in which the pressure of the gas decreases and therefore, some of the gas dissolves in solution. Thus, an increase in pressure increases the solubility of a gas in liquids while a decrease in pressure reduces the solubility.
Gas + Solvent
Solution; According to Le-Chatelier's principle:
(i) With the increase of temperature, the equilibrium shifts towards that direction where absorption of heat takes place in order to nullify the effect of the rising in temperature. In such case, the equilibrium will shift in the backward direction i.e., the solubility decreases.
(ii) With the increase of pressure, the volume is reduced. Consequently, the system proceeds in a direction in which the pressure of the gas decreases and therefore, some of the gas dissolves in solution. Thus, an increase in pressure increases the solubility of a gas in liquids while a decrease in pressure reduces the solubility.
