Question

Give name for the following substituted alkane:

Answer 1

Hint: Given compound is a cycloalkane and the parent chain is a cyclopentane ring. There is a functional group i.e., alcohol $( - OH)$ and a substituent i.e., chlorine ($ - Cl$). Also, the carbon atom with the functional group must be labelled as 1 and then further numbering is done. Alcohols are named by replacing the suffix -ane with –ol.

Complete answer:
Let us first do numbering on each carbon atom in the given compound. The carbon atom with the functional group (here, functional group is -OH) will be numbered 1. Therefore,

Given compound is cycloalkane. Cycloalkanes are cyclic hydrocarbons, meaning that the carbon atoms are arranged in the form of a ring. If we count the number of carbon atoms in our given ring, we find that they are five and these five carbon atoms constitute the longest chain in the molecule. So the parent chain is a cyclopentane ring. Since, there is an alcohol functional group on the ring, the ending of the name of the parent chain will include the suffix ‘-ol’. Thus, naming of the given molecule will be with the ending ‘cyclopentanol’. Now, a substituent is also present in the ring and that is, chlorine atom on carbon 2. Also, a dash ‘_’ must be placed between the number and the name of the substituent. So, substituent chlorine will be included in the naming with the prefix ‘2-chloro’. While writing the prefix naming with the parent chain naming, there must be no space.
Therefore, on summarising the above explanation, name of the given cycloalkane will be:
2-chlorocyclopentanol.

Note:
It should be noted that the parent chain is the one with the highest number of carbon atoms. If there are two cycloalkanes, then use the cycloalkane with the highest number of carbon atoms as the parent chain. The suffix of the name reflects the type of functional group present within the molecule. Other groups which are present in the parent chain are called substituents.