Question

The reddish-brown coloured gas formed on heating nitric acid is ______.

Options

• N₂O₅

• N₂O₄

• NO₂

• N₂O₃

Answer 1

The reddish-brown coloured gas formed on heating nitric acid is NO₂.

Explanation:

Nitric acid decomposes on heating to produce nitrogen dioxide (NO₂), water vapour, and oxygen. Nitrogen dioxide is a distinct reddish-brown gas.

\[\ce{4HNO3 ->[\Delta] 4NO2 ^ + 2H2O + O2 ^}\]