Question

Which answer provides the correct name for name the following hydrocarbon?

Answer 1

I think the correct answer would be the third option. The correct name for the hydrocarbon described above would be 2-heptyne. It has a chemical formula written as CH3 - CH2 - CH2 - CH2 - C ≡ C - CH3. Counting the number of carbons, we have 7 carbon atoms so we use the prefix hepta-. Since it has a triple bond then it is an alkyne. So, it would be named as heptyne. The triple bond is located on the second carbon atom so we write 2 before the name to indicate the location of the triple bond. The name of the compound would be 2-heptyne.

Answer 2

Answer : The correct option is, 4-methyl-2-hexyne  

Explanation :

The rules for naming of alkyne are :

• First select the longest possible carbon chain.
• The longest possible carbon chain should include the carbons of triple bonds.
• The naming of alkyne by adding the suffix -yne.
• The numbering is done in such a way that first carbon of triple bond gets the lowest number.
• The carbon atoms of the triple bond get the preference over the other substituents present in the parent chain.
• If two or more similar alkyl groups are present in a compound, the words di-, tri-, tetra- and so on are used to specify the number of times of the alkyl groups in the chain.

According to the given information, the name of the hydrocarbon is, 4-methyl-2-hexyne.

The structure of given compound is shown below.