Question

Visualize the structural formula of each of the following hydrocarbons. Which hydrocarbon has a double bond in its carbon skeleton?

(A) C₃H₈

(B) C₂H₆

(C) C₂H₄

(D) C₂H₂

Short answer

(A) The option “C₃H₈” is false.

(B) The option “C₂H₆” is false.

(C) The option “C₂H₄” is true.

(D) The option “C₂H₂” is false.

Step-by-step solution

Hydrocarbon

Certain organic compounds consist of central carbon atoms, which are bonded to hydrogen atoms.These compounds are called hydrocarbons. There are four types, namely: alkanes, alkenes, alkynes, and aromatic hydrocarbon.

Explanation of option (A)

C₃H₈is the chemical formula of propane.

The structural formula of propane is as follows:

From the above structure, it can be observed that there are two single bonds between the three carbon atoms and eight single bonds between the carbon and hydrogen atoms of propane.

Thus, the double bond is absent in the carbon skeleton of propane.

Therefore, the given option is false.

Explanation of option (B)

C₂H₆is the chemical formula of ethane.

The structural formula of ethane is as follows:

From the above structure, it can be observed that there is one single bond between the two carbon atoms and six single bonds between the carbon and hydrogen atoms of ethane.

Thus, the double bond is absent in the carbon skeleton of ethane.

Therefore, the given option is false.

Explanation of option (C)

C₂H₄is the chemical formula of ethene.

The structural formula of ethene is as follows:

From the above structure, it can be observed that there is one double bond between the two carbon atoms and four single bonds between the carbon and hydrogen atoms of ethene.

Thus, the double bond is present in the carbon skeleton of ethene.

Therefore, the given option is true.

Explanation of option (D)

C₂H₂is the chemical formula of ethyne.

The structural formula of ethyne is as follows:

From the above structure, it can be observed that there is one triple bond between the two carbon atoms and two single bonds between the carbon and hydrogen atoms of ethyne.

Thus, a triple bond is present in the carbon skeleton of ethyne, but a double bond is absent.

Therefore, the given option is false.