Why does HNO3 does not release Hydrogen gas when it reacts with any metal except Mg and Mn?

Asked by  | 20th Aug, 2011, 01:53: AM

Expert Answer:

When nitric acid reacts with strongly electropositive metals like ‘Mg’ and ‘Mn’ ,the Hydrogen ion get reduced to Hydrogen gas.

     Mg + 2 H+ ? Mg2+ + H2

Whereas with other less electropositive metals like ‘Cu’ etc the products depend on temperature and the acid concentration. For example, copper reacts with dilute nitric acid at ambient temperatures with a 3:8 stoichiometry.

3 Cu + 8 HNO3 ?3 Cu2+ + 2 NO + 4 H2O + 6 NO3-

Answered by  | 23rd Aug, 2011, 04:19: PM

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