Question

Assertion: Primary atmosphere of primitive earth was reducing.

Reason: Primary atmosphere had an abundance of NH₃, CH₄, and CO₂ but had no free oxygen.

Read the assertion and reason statements carefully and answer the question on the basis of the following options.

• A. Assertion is True, Reason is True; Reason is a correct explanation for Assertion.
• B. Assertion is True, Reason is True; Reason is not a correct explanation for Assertion.
• C. Assertion is True, Reason is False.
• D. Assertion is False, Reason is True.

Answer 1

The correct option is A

Assertion is True, Reason is True; Reason is a correct explanation for Assertion.

Correct option is (a).

Assertion Statement:

1. The primary atmosphere has an abundant amount of hydrogen, which is the lightest gas that was lost in space continuously; hence, the primary atmosphere of primitive earth was reduced.
2. So, the assertion is correct.

Reason Statement:

1. The primary atmosphere was full of hydrogen.
2. This hydrogen combines with nitrogen to form NH3, carbon to form CH4, and CO2 and oxygen to form water.
3. Hydrogen combined with oxygen results in no free molecules of oxygen.
4. The primary atmosphere of primitive earth was reducing because it had an abundance of NH3, CH4, and CO2 but had no free oxygen.
5. So, the reason is correct, so the reason is the correct explanation for assertion.

Final Answer: (A) Assertion is True, Reason is True; Reason is a correct explanation for Assertion.