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

Moving left to right: A hydrocarbon chain made of a methyl group (CH subscript three) single bond carbon triple bond carbon single bond CH bonded to a methyl group (CH subscript three) and a chain including a methelyne group (CH subscript two) single bond methyl group (CH subscript three) .

4-ethyl-2-pentyne
4-methyl-2-hexyne
2-heptyne
4-methy-hexane

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.

BarrettArcher BarrettArcher · Answer 2 · 2019-05-29T07:23:39+02:00

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.