Question

Consider the chemical reaction, $N_2\left(g\right)+3H_2\left(g\right)⟶2N{H}_3\left(g\right)$.
The rate of reaction can be expressed in terms of time derivative of concentration of $N_2\left(g\right),H_2\left(g\right)$ or $N{H}_3\left(g\right)$. Identify the correct relationship amongst the rate expressions.

• A. Rate $=-\frac{d\left[N_2\right]}{dt}=-\frac{1}{3}\frac{d\left[H_2\right]}{dt}=+\frac{1}{2}\frac{d\left[N{H}_3\right]}{dt}$
• B. Rate $=-\frac{d\left[N_2\right]}{dt}=-3\frac{d\left[H_2\right]}{dt}=+2\frac{d\left[N{H}_3\right]}{dt}$
• C. Rate $=\frac{d\left[N_2\right]}{dt}=\frac{1}{3}\frac{d\left[H_2\right]}{dt}=\frac{1}{2}\frac{d\left[N{H}_3\right]}{dt}$
• D. Rate $=-\frac{d\left[N_2\right]}{dt}=-\frac{d\left[H_2\right]}{dt}=\frac{d\left[N{H}_3\right]}{dt}$

Answer 1

The correct option is A Rate $=-\frac{d\left[N_2\right]}{dt}=-\frac{1}{3}\frac{d\left[H_2\right]}{dt}=+\frac{1}{2}\frac{d\left[N{H}_3\right]}{dt}$

$\vartheta =\frac{-d}{dt}\left[N_2\right]=-\frac{1}{3}\frac{d}{dt}\left[H_2\right]=\pm \frac{1}{2}\frac{d}{dt}\left[{NH}_3\right]$