Question

Identify the anion present in the following compound:

Compound X on heating with copper turnings and conc. sulphuric acid liberates a reddish brown gas.

Answer 1

The anion present in compound X is nitrate ion \[\ce{(NO^{-}_3)}\].

Explanation:

On heating with copper turnings and concentrated sulphuric acid, nitrate produces nitrogen dioxide (NO₂​), a reddish-brown gas.

\[\ce{Cu + 4HNO3​(conc{.}) →Cu(NO3​)2 + 2NO2​↑ + 2H2​O}\]

Therefore, the reddish-brown gas confirms the presence of the nitrate ion \[\ce{(NO^{-}_3)}\].