Question

The calorific values of three fuels A, B and C are 33 kJ/g, 48 kJ/g and 150 kJ/g, respectively. A is solid, B is liquid and C is a gas at room temperature. One combustion, both A and B produce carbon dioxide while C explodes forming steam. B and C leave no residue after combustion while A leaves behind some solid residue. Which one of the three fuels is the most ideal? Give two reasons to support your answer.

Answer 1

Fuel A has a low calorific value compared with the other fuels, and therefore, it cannot be considered the most ideal fuel.

Fuel B is the most ideal fuel of the three for the following reasons.
(a) It has a high calorific value.
(b) It burns completely without leaving any residue.
 
Fuel C has both the characteristics of fuel B but is unsafe as it explodes.

Hence, B is the ideal fuel.