Question

Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when
metals (except Mn and Mg), are treated particularly with HINO3, hydrogen is not liberated,
why?​

Answer 1

Explanation:

Because Nitric acid(HNO3) is a strong oxidising agent. So as soon as hydrogen gas is formed in the reaction between a metal and dilute nitric acid, the HNO3 oxidises this hydrogen to water and itself gets reduced to NO or NO2 or N2O. So in the reaction of metals (except MN and mg) with nitric acid no hydrogen gas is evolved.