Question

Concentrated nitric acid on reacting with any metal like copper releases gas with an irritating odour :

• A. $H_{2}S$
• B. $CuS$
• C. $H_2$
• D. $N{O}_2$

Answer 1

The correct option is D $N{O}_2$

Nitrogen dioxide is the chemical compound with the formula $N{O}_2$. It is one of several nitrogen oxides. $N{O}_2$ is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent air pollutant. Reduction of concentrated nitric acid by metal (such as copper).
$4HN{O}_3+Cu\to Cu(N{O}_3{)}_2+2N{O}_2+2H_{2}O$