Question

Assertion: Hydrogen gas has the highest calorific value.

Reason: Hydrogen is the lightest gas and hence produces a large amount of heat.

• A. Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’.
• B. Both ‘A’ and ‘R’ are correct, but ‘R’ is not the correct explanation of ‘A’.
• C. ‘A’ is correct, but ‘R’ is incorrect
• D. ‘A’ is incorrect, but ‘R’ is correct

Answer 1

The correct option is C

‘A’ is correct, but ‘R’ is incorrect

The explanation for the assertion:

1. The heat produced per gram of fuel on complete combustion in oxygen is called its calorific value.
2. Hydrogen gas has the highest calorific value of 150 kJ g^-1.

The explanation for the reason:

1. The calorific value of a substance is independent of the weight of the substance.

Hence, the answer is (C) A is correct, but R is incorrect.