question_answer 71)

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

Answer:

                  Nitric acid (HNO3) is a strong oxidizing agent. So, as soon as hydrogen gas is formed in the reaction between a metal and dilute nitric acid, the nitric acid oxidizes this hydrogen to water and itselyHNO3gets reduced tooror. So, in the reaction of metals (except Mn and Mg), with dilute nitric acid, no hydrogen gas is evolved.