Question

Write IUPAC name of the following:

Answer 1

:Hint: We know that in order to name organic compounds we must first know that the cycloalkanes only contain carbon-hydrogen bonds and carbon-carbon single bonds, but in cycloalkanes, the carbon atoms are joined in a ring. The groups which are attached to the parent chain are called substituents. If we count the carbons and hydrogens, we will see that the cycloalkanes no longer fit the general formula ${C_n}{H_{2n + 2}}$ . By joining the carbon atoms in a ring, two hydrogen atoms have been lost. The general formula for a cycloalkane is ${C_n}{H_{2n}}$ .

Complete answer:
Cyclic compounds are not all flat molecules. All of the cycloalkanes, from cyclopentane upwards, exist as "puckered rings".
In addition to being saturated cyclic hydrocarbons, cycloalkanes may have multiple substituents or functional groups that further determine their unique chemical properties. Since, the given compound is cyclopentane and there is a methyl attached at number 3 carbon. Alcohol $\left( { - OH} \right)$ substituents take the highest priority for carbon atom numbering in IUPAC nomenclature. The carbon atom with the alcohol substituent is labelled 1. So, the molecules that contain an alcohol group have an ending “$-ol$”, and indicates the presence of an alcohol group. And, here alcohol is attached at 1 carbon.

So, the IUPAC name is 3 - methyl cyclopentanol.
Note:
We should note that we use the cycloalkane as the parent chain if it has a greater number of carbons than any alkyl substituent and If an alkyl chain off the cycloalkane has a greater number of carbons, then use the alkyl chain as the parent and the cycloalkane as a cycloalkyl- substituent. When numbering the carbons of a cycloalkane, start with a substituted carbon so that the substituted carbons have the lowest numbers (sum). When two or more different substituents are present, number according to alphabetical order.