Question

Which fuel has the highest calorific value?
A. Hydrogen gas
B. Methane
C. Wood
D. Petrol

Answer 1

Hint: In order to get the correct answer you need to know the calorific value is the amount of energy produced by the complete combustion of a material or fuel.

Complete step-by-step answer:

Calorific value is nothing but the energy contained in a fuel or food, determined by measuring the heat produced by the complete combustion of a specified quantity of it. This is now usually expressed in joules per kilogram.

Fuels with calorific values:

1. Hydrogen: 150 KJ/g

2. Methane: 55 KJ/g

3. LPG: 50 KJ/g

4. Kerosene oil:48 KJ/g

5. Charcoal: 33 KJ/g

6. Wood: 17 KJ/g

Hence, hydrogen has the highest calorific value.
So, the correct option is A.

Note: To solve such problems we need to learn the calorific values of some common elements. The reaction between hydrogen and oxygen to produce water is highly exothermic and the heat liberated is 285 kJ/mole. Such a vast difference in the heat of combustion between hydrogen and the other fuels sufficiently explains its very high calorific value.