Question

Which of the following gas has the highest heat of combustion
A) Methane B) Ethane C) Ethylene D) Acetylene

Answer 1

gas has the highest heat of combustion is methane

Answer 2

Answer: Option (B) is the correct answer.

Explanation:

When 1 mole of a substance completely burns then the amount of energy released is known as heat of combustion.

And, a hydrocarbon which contains more number of carbon atoms that are combine together through single bonds will have the highest heat of combustion.

Chemical formula of ethylene is $C_{2}H_{4}$. This means there is a double bond between the carbon atoms.

As the chemical formula of acetylene is $C_{2}H_{2}$. This means that there is a triple bond between the carbon atoms.

Chemical formula of ethane is $C_{2}H_{6}$ and there is a single bond between the carbon atoms.

Whereas in methane there are less number of single bonds as compared to ethane.

Thus, we can conclude that out of the given options ethane gas has the highest heat of combustion.