Question

Arrange the following fuels in the order of decreasing calorific values (keeping the fuel with highest calorific value first):
Biogas, Kerosene, Wood, Petrol, Hydrogen gas, Methane 

Answer 1

The fuels in the decreasing order of calorific values are as follows.
   
Hydrogen gas (150 kJ/g) > Methane (55 kJ/g) > Petrol (50 kJ/g) > Kerosene (48 kJ/g) > Biogas (40 kJ/g) > Wood (17 kJ/g)