Question

Complete the following reaction
$\mathrm{Cu}+{\mathrm{HNO}}_3\to \mathrm{Cu}({\mathrm{NO}}_3{)}_2+H_{2}O+$

• A. $N{O}_2$
• B. $N{O}_3$
• C. $O_2$

Answer 1

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

$\mathrm{Cu(s)\; +\; 4HNO3\; (conc)\; \to Cu(NO3)2(aq)\; +\; H2O(l)\; +\; NO2(g)}$The above reaction can be used to check whether the given sample of acid is nitric acid. In this reaction, pieces of $Cu$ are treated with nitric acid. The yellow-brown fumes of $N{O}_2$ released confirm the acid.
Except $Mg$ and $Mn$, all other metals react with nitric acid to give $H_{2}O$ as one of the products, while $Mg$ and $Mn$ release $H_2$ gas.