Question

Which of the following is/are false regarding nitric acid?

• A. It can dissolve $Cr$ and $Al$ metal
• B. It is a strong oxidizing agent
• C. Its basicity is 2
• D. It is non-planar in gaseous state

Answer 1

Answer: (A), (C), (D)

It is non-planar in gaseous state

Nitric acid has a polar $O–H$ bond. This bond breaks to donate the $H^{+}$ ion which is why it is a strong oxidizing agent and a strong acid. Since there is only one cleavable $O–H$ bond, the basicity of nitric acid is unity (one $HN{O}_3$ molecule can donate only one $H^{+}$ ion). It exists as a planar molecule in gaseous state.
Metals like Cr, Al, etc do not dissolve in concentrated nitric acid because of the formation of passive film of oxide on its surface.
Hence, statements (a), (c) and (d) are flase.