Answer these questions selecting the appropriate option given below:
Assertion (A) : Hydrogen gas is not evolved when a metal reacts with nitric acid.
Reason (R) : Nitric acid is a strong oxidizing agent.
Answer & explanation
Correct answer: option 1
The correct answer is option 1. Both A and R are true and R is the correct explanation of A.
Assertion (A): Hydrogen gas is not evolved when a metal reacts with nitric acid. - This statement is true. Unlike most acids where a metal replacement reaction produces hydrogen gas, reacting a metal with nitric acid does not typically result in hydrogen gas evolution.
Reason (R): Nitric acid is a strong oxidizing agent. - This statement is also true. Nitric acid (HNO₃) is a strong acid that readily accepts electrons, making it a powerful oxidizing agent.
The key concept lies in how nitric acid behaves during the reaction:
When a metal reacts with a dilute nitric acid solution, the metal displaces hydrogen from the acid. However, the oxidizing nature of nitric acid comes into play.
Nitric acid readily oxidizes the displaced hydrogen gas (H₂) to water (H₂O) by accepting electrons from the hydrogen.
This effectively consumes the hydrogen that would otherwise be released as a gas.
Therefore, both the assertion and the reason are true, and the reason explains why hydrogen gas isn't typically observed when a metal reacts with nitric acid.