Question
Applying Le-Chatelier’s principle predict the effect of temperature on the solubility of solid substances.
Solution
Certain salts like ammonium chloride dissolve with the absorption of heat (endothermic reaction). Such reactions can be represented as:
According to Le-Chatelier’s principle, on increasing temperature, the equilibrium shifts towards that direction where absorption of heat (endothermic change) takes place in order to nullify the effect of the rise in temperature. Hence solubility of such salts increases with the increase in temperature.
On the other hand, certain salts like sodium hydroxide dissolve with the evolution of heat. The equilibrium may be represented as:
Applying Le-Chatelier’s principle, on increasing temperature, the equilibrium shifts towards that direction where absorption of heat takes place i.e. backwards reaction favours. Hence, the solubility of such salts decreases with the rise in temperature.
According to Le-Chatelier’s principle, on increasing temperature, the equilibrium shifts towards that direction where absorption of heat (endothermic change) takes place in order to nullify the effect of the rise in temperature. Hence solubility of such salts increases with the increase in temperature.
On the other hand, certain salts like sodium hydroxide dissolve with the evolution of heat. The equilibrium may be represented as:
Applying Le-Chatelier’s principle, on increasing temperature, the equilibrium shifts towards that direction where absorption of heat takes place i.e. backwards reaction favours. Hence, the solubility of such salts decreases with the rise in temperature.
