Give balanced equations for the following:

(i) Laboratory preparation of nitric acid.

(ii) Action of heat on a mixture of copper and concentrated nitric acid.

(i) Balanced equation for laboratory preparation of nitric acid:

$\underset{[conc.]}{\text{KNO}$3} + \underset{[conc.]}{\text{H}2\text{SO}4} \xrightarrow{\lt 200 \degree\text{C}} \underset{[acid \space salt]}{\text{KHSO}4} + \text{HNO}_3

(ii) Balanced equation for action of heat on a mixture of copper and concentrated nitric acid:

$\text{Cu} + 4\underset{[conc.]}{\text{HNO}$3} \longrightarrow \text{Cu(NO}3 \text{)}2 + 2\text{H}2 \text{O} + 2\text{NO}_2