Question

In a catalytic experiment involving the Haber process,
$N_{2(g)}+3H_{2(g)}\to 2N{H}_{3(g)}$
the rate of reaction was measured as
Rate $=\left[N{H}_3\right]=2.0\times 10^{-4}M{s}^{-1}$ .If there were no side reactions what was the rate of reaction expressed in terms of $N_2$ ?

• A. $1\times 10^{-4}M{s}^{-1}$
• B. $4\times 10^{-4}M{s}^{-1}$
• C. $5\times 10^{-3}M{s}^{-1}$
• D. $1\times 10^{-3}M{s}^{-1}$

Answer 1

Answer: (A)

Given, rate $=2.0\times 10^{-4}M{s}^{-1}$
For the reaction, $N_2(g)+3H_2(g)\to 2N{H}_3(g)$
$-\frac{d\left[N_2\right]}{dt}=-\frac{d\left[H_2\right]}{3dt}=+\frac{d\left[N{H}_3\right]}{2dt}$
$\frac{-d\left[N_2\right]}{dt}=\frac{d\left[N{H}_3\right]}{2dt}$
$=\frac{2.0\times 10^{-4}}{2}=1.0\times 10^{-4}M{s}^{-1}$