Hydrogen gas is not evolved when a metal reacts with nitric acid. It is because HNO3 is a strong oxidising agent. ... But magnesium (Mg) and manganese (Mn) react with very dilute HNO3 to evolve H2 gas.

Nitric acid is a strong oxidizing agent and is commonly used in the laboratory for various purposes. When nitric acid comes in contact with certain metals, it reacts with the metal to produce hydrogen gas. In this article, we will discuss two such metals that evolve hydrogen gas with nitric acid.





Zinc is a bluish-white, lustrous metal that is commonly used in galvanizing steel to prevent rusting. When zinc is added to nitric acid, it reacts with the acid to produce hydrogen gas according to the following chemical equation:

Zn + 2HNO3 → Zn(NO3)2 + H2

The reaction between zinc and nitric acid is an example of a single displacement reaction, where the zinc atom replaces the hydrogen atom in the nitric acid molecule. The reaction is highly exothermic, and the evolved hydrogen gas can ignite if exposed to a spark.



Magnesium is a silvery-white metal that is commonly used in the manufacture of aircraft and automobile parts. When magnesium is added to nitric acid, it reacts with the acid to produce hydrogen gas according to the following chemical equation:

Mg + 2HNO3 → Mg(NO3)2 + H2

The reaction between magnesium and nitric acid is also an example of a single displacement reaction, where the magnesium atom replaces the hydrogen atom in the nitric acid molecule. The reaction is highly exothermic, and the evolved hydrogen gas can ignite if exposed to a spark.



In conclusion, zinc and magnesium are two metals that evolve hydrogen gas with nitric acid. The reaction between these metals and nitric acid is highly exothermic, and the evolved hydrogen gas can ignite if exposed to a spark. It is important to handle these reactions with care and under proper safety precautions.