Question

Which one of the following has the highest calorific value?

• A. kerosene
• B. biogas
• C. LPG
• D. petrol

Answer 1

The correct option is C

LPG

Explanation for correct option

(C) LPG

Combustion

• When a chemical combines with oxygen gas, energy is released in the form of light and heat.
• The presence of oxygen gas as a reactant in combustion processes is required.
• Example: Water vapor is produced by the combustion of hydrogen gas.
• The quantity of energy released or created by burning $1\mathrm{kg}$ of fuel is known as its calorific value.
• Higher calorific value refers to the total amount of heat released during the combustion of a given fuel at a particular mass or volume when byproducts and byproduct cooling are permitted to occur at room temperature.
• Lower calorific value refers to the total amount of heat released during the combustion of a specific fuel at a given mass or volume when side products are allowed to leave.

Calorific values

• For kerosene, it is $43.1\mathrm{MJ}{\mathrm{kg}}^{-1}$.
• For Biogas, it is $19-25\mathrm{MJ}{\mathrm{m}}^{-3}$
• For LPG (Liquified petroleum gas), it is $46.1\mathrm{MJ}{\mathrm{kg}}^{-1}$.
• For petrol, it is $45.8\mathrm{MJ}{\mathrm{kg}}^{-1}$.

Explanation for incorrect options

• The LPG has the highest calorific value which is $46.1\mathrm{MJ}{\mathrm{kg}}^{-1}$..
• Hence, all other options (A), (B) and (D) are incorrect.

Therefore the correct option is (C) LPG.