Question

In the preparation of $HN{O}_3$, we get $NO$ gas by the catalytic oxidation of ammonia. The moles of $NO$ produced by the oxidation of two moles of $N{H}_3$will be _____________.

• A. $3$
• B. $6$
• C. $2$
• D. $4$

Answer 1

The correct option is C $2$

$\text{Ostwald process}$

• In Ostwald process, $HN{O}_3$ is prepared from $N{H}_3$ on a large scale.
• This method is based on the catalytic oxidation of $N{H}_3$ by atmospheric oxygen.

$4N{H}_3\left(g\right)+5O_2\left(g\right)\to 4NO\left(g\right)+6H_{2}O\left(g\right)$

• Then, $NO$ is further oxidised to $N{O}_2$, which dissolves in $H_{2}O$ to give $N{H}_3$.
• The given chemical reaction is for $4$ moles of $N{H}_3$. So, the reaction for $2$ moles of ammonia is:

$2N{H}_3\left(g\right)+\frac{5}{2}{O}_2\left(g\right)\to 2NO+3H_{2}O$

• Therefore, $2$ moles of $NO$ are produced.

So, option $\left(A\right)$ is the correct answer.