Question

One mole of $HN{O}_3$ absorbs one mole of electrons in a redox reaction. The reduced product of this reaction is :

• A. $1$ mole $N_2$
• B. $1$ mole $N_{2}O$
• C. $1$ mole $N{O}_2$
• D. $1$ mole $N{H}_3$

Answer 1

Answer: (C)

$1$ mole $N{O}_2$

The oxidation state of $N$ in $HN{O}_3$ is $+5$.
If it takes one mole of electrons, then oxidation state of $N$ will be $+4$.
So, product formed will be $N{O}_2$ ($+4$ oxidation state of $N$) and one mole of it will be formed.
Compound Oxidation state
$N_{2}O$ +2
$N_2$ 0
$N{H}_3$ -3