Question

The $\%$ yield of ammonia as a function of time in the reaction $N_{2(g)}+3H_{2(g)}\rightleftharpoons 2N{H}_{3(g)}$, $\Delta H<0$ at $(P,T_1)$ is given below.

If this reaction is conducted at $(P,T_2)$, with $T_2>T_1$, the $\%$ yield of ammonia as a function of time is represented by

• A.
• B.
• C.
• D.

Answer 1

Answer: (B)

$N_{2(g)}+3H_{(g)}\underset{endo}{\overset{exo}{\rightleftharpoons }}2NH{3}_{(g)}$; $\Delta H<0$
Initially, with increase in temperature $(T_2>T_1)\%$ yield increases.
Afterwards, equilibrium is reached and if the temperature is increased, i.e., heat is supplied to the system, then according to Le Chatelier's principle, the equilibrium will shift in the backward direction, where the heat is absorbed. Hence, the $\%$ yield decreases.