Question

How does temperature affect dynamic equilibrium?

Answer 1

Hint:Dynamic equilibrium is a condition at which the reaction rate of the forward reaction is equal to the reaction rate of the backward reaction. Whenever there is change in concentration, pressure, temperature the equilibrium gets disturbs. In such cases Le-Chatelier’s principle comes into play which restores the equilibrium.

Complete step-by-step answer:Temperature is one factor which can disturb the equilibrium in a reaction. According to Le-Chatelier's principle when the temperature of the system is changed, the equilibrium shifts in the opposite direction in order to neutralize the effect of change in temperature.
For example, the formation of ammonia is an exothermic reaction while the reverse reaction is an endothermic reaction. The equilibrium in the reaction is
${{N}_{2}}\left( g \right)+3{{H}_{2}}\left( g \right) \to 2N{{H}_{3}}\left( g \right);\,\Delta H=-92.5kJ$
In the above reaction if the temperature of the reaction mixture is increased, the equilibrium gets shifted to the left in order to neutralize or undo the effect of increase in temperature. Actually, backward reaction is accompanied by a decrease in temperature or cooling.
 Similarly, in case if the temperature is decreased, then the equilibrium will be shifted to the right because heat is evolved in the forward reaction.
In a similar manner, we can conclude that the effect of temperature in the formation of nitric oxide which is of endothermic nature.
${{N}_{2}}\left( g \right)+{{O}_{2}}\left( g \right) \to 2NO\left( g \right);\,\Delta H=+180.0kJ$
So, we understand that increase in temperature will shift the equilibrium to the right while the decrease in temperature will shift it to the left because only then the effect of change in temperature will be neutralized or undone.

Note: It should be hence noted that the increase in temperature shifts the equilibrium in the forward direction in the endothermic reaction. And the decrease in temperature shifts the equilibrium in the forward direction in exothermic reaction.