Question

The reaction below is allowed to come to equilibrium. After equilibrium is reached, the temperature of the container is raised by 50ºC. Which statement below describes a change that will be observed as the system returns to an equilibrium state at the new temperature if ΔH is positive?
2 NH3(g) ⇄ N2(g) + 3 H2(g)

a. The concentration of ammonia, NH3, will increase.
b. The concentration of nitrogen gas, N2, will decrease.
c. The rate of the forward reaction will increase.
d. There will be no change; increasing the temperature will not change the position of equilibrium.

Answer 1

Answer: c. The rate of the forward reaction will increase.

Explanation:

Any change in the equilibrium is studied on the basis of Le-Chatelier's principle.

This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.

For the given equation:

$2NH_3(g)\rightleftharpoons N_2(g)+3H_2(g)$  $\Delta H=+ve$

This is a type of Endothermic reaction because heat is absorbed in the reaction.

When the temperature  is increased, according to the Le-Chatlier's principle, the equilibrium will shift in the direction where decrease in temperature occurs. As, this is an endothermic reaction, forward reaction will decrease the temperature. Hence, the equilibrium will shift in the right or forward direction.