Question

_____gas is produced when action of concentrated nitric acid on copper.

Answer 1

• When concentrated Nitric acid is treated with copper, copper is oxidized to Cupric nitrate or Copper(II) nitrate, and water and Nitrogen dioxide gas is formed.
• The reaction involved is:

$\underset{\mathrm{Copper}}{\mathrm{Cu}\left(\mathrm{s}\right)}+\underset{\mathrm{Nitric}\mathrm{acid}}{4{\mathrm{HNO}}_3\left(\mathrm{aq}\right)}\to \underset{\mathrm{Cupric}\mathrm{nitrate}}{\mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{water}}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}+\underset{\mathrm{Nitrogen}\mathrm{dioxide}}{2{\mathrm{NO}}_2\left(\mathrm{g}\right)}$

• Nitrogen dioxide is brown in color and is a poisonous gas.

Hence, Nitrogen dioxide $\left({\mathrm{NO}}_2\right)$ gas is produced when the action of concentrated Nitric acid on copper.