Question

Fill in the blanks using the appropriate words given below :
(Sulphur dioxide, Nitrogen dioxide, Nitric oxide, Sulphuric acid)
(i) Cold, dilute nitric acid reacts with copper to give ____________.
(ii) Hot, concentrated nitric acid reacts with copper to form ____________.

Answer 1

(i) Reaction of copper with cold dilute nitric acid is:

$\underset{copper}{3Cu\left(s\right)}+\underset{nitricacid}{8H{NO}_3\left(aq\right)}\to \underset{coppernitrate}{3Cu{\left({NO}_3\right)}_2\left(aq\right)}+\underset{water}{{4H}_{2}O\left(l\right)}+\underset{nitricoxide}{2NO\left(g\right)}$

Gas evolved is nitric oxide.

(ii) $Cu+4HN{O}_3\to Cu(N{O}_3{)}_2+2H_{2}O+2N{O}_2$

With hot nitric acid Nitrogen dioxide is liberated.