Reaction of Calcium with Dilute Nitric Acid:

When calcium reacts with dilute nitric acid, the following reaction takes place:

Ca + 2HNO3 → Ca(NO3)2 + H2

- Introduction: The reaction between calcium and dilute nitric acid is a redox reaction, where calcium is oxidized while nitric acid is reduced.

- Oxidation of Calcium: The calcium atoms lose two electrons each to form calcium ions (Ca2+), which is the oxidation process.

- Reduction of Nitric Acid: Nitric acid (HNO3) is reduced to nitrogen dioxide (NO2) gas. In the process, the nitrogen in nitric acid changes its oxidation state from +5 to +4.

- Formation of Calcium Nitrate: The calcium ions (Ca2+) combine with nitrate ions (NO3-) from the nitric acid to form calcium nitrate (Ca(NO3)2), which is a white, crystalline solid.

- Release of Hydrogen Gas: The reaction also produces hydrogen gas (H2) as a byproduct. The hydrogen gas is released as bubbles.

Reaction of Magnesium with Dilute Nitric Acid:

When magnesium reacts with dilute nitric acid, the following reaction occurs:

Mg + 2HNO3 → Mg(NO3)2 + H2

- Introduction: The reaction between magnesium and dilute nitric acid is a redox reaction, similar to the reaction with calcium.

- Oxidation of Magnesium: Magnesium atoms lose two electrons each to form magnesium ions (Mg2+), which is the oxidation process.

- Reduction of Nitric Acid: Nitric acid (HNO3) is reduced to nitrogen dioxide (NO2) gas, similar to the reaction with calcium.

- Formation of Magnesium Nitrate: The magnesium ions (Mg2+) react with nitrate ions (NO3-) from the nitric acid to form magnesium nitrate (Mg(NO3)2), which is a white, crystalline solid.

- Release of Hydrogen Gas: The reaction also produces hydrogen gas (H2) as a byproduct, which is released as bubbles.

Conclusion:

In both reactions, the metals (calcium and magnesium) are oxidized, losing electrons, while the nitric acid is reduced. The products formed are the respective metal nitrates and hydrogen gas. The reaction between these metals and dilute nitric acid is an example of a displacement reaction, where the more reactive metal displaces the less reactive hydrogen from the acid.

Ca + 4 HNO3 ------------> Ca(NO3)2 + 2 H2O + 2 NO2 . Mg+2HNO3--------->Mg(NO3)2+H2