Question

Consider the following reaction :

$Cu+4HN{O}_3\left(dil\right)\to Cu(N{O}_3{)}_2+2H_{2}O+2NO$

Which of the following statement is correct?

• A. $HN{O}_3$ is the oxidant whereas $Cu$ is the reductant.
• B. $Cu$ is the oxidant whereas $H_{2}O$ is the reductant.
• C. $Cu$ is the oxidant whereas $HN{O}_3$ is the reductant.
• D. None of the above

Answer 1

The correct option is A $HN{O}_3$ is the oxidant whereas $Cu$ is the reductant.

In the following redox reaction:
$Cu+4HN{O}_3\left(dil\right)\to Cu(N{O}_3{)}_2+2H_{2}O+2NO$
Oxidation states,
$0\text{for}Cu+5\text{for}N+4\text{for}Cu+2\text{for}N$

Oxidation state of $Cu$ is increasing so it is being oxidised by $HN{O}_3$. So, $HN{O}_3$ is the oxidant.

Oxidation state of $N$ is decreasing so it is being reduced by $Cu$. So, $Cu$ is the reductant.