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

To answer which fuel has the highest calorific value, let's break down the calorific value of each fuel mentioned in the options:
Calorific Value
The calorific value of a fuel is the amount of heat energy released when a unit quantity of fuel is completely burned. It is usually measured in kJ/g or MJ/kg.
A) Hydrogen Gas
• Hydrogen has a very high calorific value because it is a highly energetic fuel. The calorific value of hydrogen is around 141.9 MJ/kg.
• Hydrogen gas releases a lot of energy when burned, but due to its low density and the challenges involved in storing and handling it, it is less commonly used in many applications compared to other fuels.
B) Methane
• Methane, a primary component of natural gas, also has a high calorific value. Its calorific value is around 55.5 MJ/kg.
• Methane is commonly used as a fuel for cooking and heating, and it is more practical than hydrogen due to its easier storage and distribution.
C) Wood
• The calorific value of wood varies depending on the type of wood, but it is generally lower compared to gases like hydrogen and methane. The calorific value of wood is typically in the range of 15 to 20 MJ/kg.
• Wood is a renewable energy source, commonly used for heating and cooking in rural areas, but it is less efficient than gases or liquid fuels in terms of energy release.
D) Petrol
• Petrol (gasoline) is a widely used fuel in internal combustion engines. Its calorific value is around 44 to 46 MJ/kg.
• While petrol has a high energy content, it is not as high as hydrogen and methane.
Conclusion:
Among the fuels listed, hydrogen gas has the highest calorific value at approximately 141.9 MJ/kg. While it is not as widely used due to storage and handling challenges, hydrogen holds the highest energy per unit mass.
Correct Answer:
A)Hydrogen gas\boxed{A) \text{Hydrogen gas}}