Question

Which fuel has the highest calorific value?

A.)Hydrogen gas
B.)Methane
C.)Wood
D.)Petrol

Answer 1

Hint: The calorific value is the measurement of heat or energy produced during combustion. In the process of combustion, water vapour generates and certain techniques may be used to recover the quantity of heat contained in this water vapor by condensing it.

Complete step by step answer:
The sources of heat energy for our domestic and industrial purposes wood, charcoal, petrol, kerosene, etc. These substances are known as fuels.
The amount of heat energy produced by the complete combustion of 1 kilogram of a fuel is called its calorific value (when it is expressed in joule/kg).

Calorific values chart of some fuels:

Fuel	Calorific Value (kJ/kg)
Cow dung cake	6000-8000
Wood	17000-22000
Coal	25000-33000
Petrol	45000
Kerosene	45000
Diesel	45000
Methane	50000
CNG	50000
LPG	55000
Biogas	35000-40000
Hydrogen	150000

From the above table, we have observed that hydrogen has the highest calorific value.
Hence, the correct option is A, i.e., Hydrogen gas

Additional Information:
Majorly there are three fossil fuels i.e., coal, petroleum and natural gas.
Coal has been used extensively throughout the industrialized world since the beginning of the industrial revolution. It can be mined from deep under the ground or deposits close to the surface can be strip-mined. The main use of coal in the combustion process is to provide electricity or heat. Coal has the highest carbon-to-hydrogen ratio and the lowest calorific value among widely used three fossil fuels.

Petroleum has increased its usage significantly since the 1950s with massive increases in the use of transport fuels, which are almost exclusively supplied from petroleum, and the growth of the petrochemical industry. Petroleum is extracted as a liquid from wells on both land and sea.

Note: Students should try to memorize the calorific values of some common fuels. The reaction between hydrogen and oxygen for producing water is highly exothermic so there is a great difference between the heat of combustion of hydrogen and other fuels which is the reason behind such a high calorific value of hydrogen.