Question
Applying Le-Chatelier’s principle, predict the effect of pressure and temperature on the melting of ice.
Solution
The equilibrium may be represented as
The change of ice into water is a reversible endothermic (i.e. accompanied by absorption of heat) process. The reaction involves a decrease in volume. Hence according to Le-Chatelier’s principle:
(i) With the increase in pressure: The equilibrium tends to shift in that direction in which there occurs a decrease in the volume. So in this case, an increase in pressure favours the conversion of ice into water.
(ii) With the increase in temperature: The equilibrium shifts to the right i.e. towards the direction in which heat is absorbed. Thus, increase in temperature favours melting of ice.
