Question

Draw the structures for two examples of unsaturated hydrocarbons. What structural feature makes a hydrocarbon unsaturated?

Short answer

Two examples of unsaturated hydrocarbons are ethene (C2H4) with structure: H H \ / C = C / \ H H and ethyne (C2H2) with structure: H \ C ≡ C / H The structural feature that makes a hydrocarbon unsaturated is the presence of a double or triple bond between carbon atoms.

Step-by-step solution

1. What is an unsaturated hydrocarbon?

An unsaturated hydrocarbon is a hydrocarbon that contains at least one double or triple bond between carbon atoms. Unsaturated hydrocarbons can be classified into two main groups: alkenes, which contain at least one carbon-carbon double bond (C=C), and alkynes, which contain at least one carbon-carbon triple bond (C≡C).

2. Identify the structural feature that makes a hydrocarbon unsaturated

The structural feature that makes a hydrocarbon unsaturated is the presence of a double or triple bond between carbon atoms.

3. Example 1: An alkene - Ethene (C2H4)

Ethene, commonly known as ethylene, is an alkene. Its molecular formula is C2H4. The structure of ethene is as follows: H H \ / C = C / \ H H In the ethene molecule, there is a carbon-carbon double bond (C=C) between the two carbon atoms. This makes ethene an unsaturated hydrocarbon.

4. Example 2: An alkyne - Ethyne (C2H2)

Ethyne, commonly known as acetylene, is an alkyne. Its molecular formula is C2H2. The structure of ethyne is as follows: H \ C ≡ C / H In the ethyne molecule, there is a carbon-carbon triple bond (C≡C) between the two carbon atoms. This makes ethyne an unsaturated hydrocarbon. In conclusion, two examples of unsaturated hydrocarbons are ethene and ethyne. The structural feature that makes a hydrocarbon unsaturated is the presence of a double or triple bond between carbon atoms.