Question

For the reaction $N_2\left(g\right)+3H_2\left(g\right)\to 2N{H}_3\left(g\right),$
What will be the ratio of rate of formation of $N{H}_3\left(g\right)$ to rate of consumption of $N_2\left(g\right)$?

• A. $1:3$
• B. $1:1$
• C. $1:2$
  
• D. $2:1$

Answer 1

The correct option is D $2:1$

For
$N_2\left(g\right)+3H_2\left(g\right)\to 2N{H}_3\left(g\right)$
$\text{Overall rate}\left(r\right)=-1\times \frac{d\left[N_2\right]}{dt}=-\frac{1}{3}\times \frac{d\left[H_2\right]}{dt}=+\frac{1}{2}\times \frac{d\left[N{H}_3\right]}{dt}$

$\Rightarrow -1\times \frac{d\left[N_2\right]}{dt}=+\frac{1}{2}\times \frac{d\left[N{H}_3\right]}{dt}$

$-\frac{d\left[N_2\right]}{dt}=\text{rate of consumption of}{N}_2$

$+\frac{d\left[N{H}_3\right]}{dt}=\text{rate of formation of}N{H}_3$

$\frac{\text{Rate of formation of}N{H}_3}{\text{Rate of consumption of}{N}_2}=\frac{+\frac{d\left[N{H}_3\right]}{dt}}{-\frac{d\left[N_2\right]}{dt}}=\frac{2}{1}\text{Desired Ratio}=2:1$