Question

Which one of the following is a tertiary alcohol?
(A) $C{H}_{3}C{H}_{2}C{H}_{2}OH$
(B) $C{H}_{3}CH(OH)C{H}_3$
(C) $(C{H}_3{)}_{2}CHC{H}_{2}OH$
(D) $(C{H}_3{)}_{3}COH$

Answer 1

Hint :We know that tertiary carbons are only found in branched hydrocarbons but not in linear hydrocarbons. Observe all the given options and check which hydrocarbons are linear. Then we can eliminate these linear hydrocarbons and check other alcohols.

Complete Step By Step Answer:
In a tertiary alcohol, the alcohol group is attached to a tertiary carbon. A carbon atom that is bounded to three other carbon atoms is called a tertiary carbon atom. Observe the alcohol given in the first option, it is linear and not branched. So, it is not a tertiary alcohol. Observing the alcohol given in the second option, the carbon attached to the alcohol is connected to only two carbon atoms. So, it is not a tertiary alcohol. Observing the alcohol given in the third option, the carbon attached to the alcohol is connected to only one carbon atom. So, it is not a tertiary alcohol. Observing the alcohol given in the last option, the carbon attached to the alcohol is connected to three other carbon atoms. So, it is a tertiary alcohol. $(C{H}_3{)}_{3}COH$ is a tertiary alcohol as the $-OH$ group is attached to a tertiary carbon atom.
Therefore, option D is the correct answer.

Note :
Note that a tertiary carbon atom is found only in hydrocarbons which contain at least four carbon atoms. Tertiary carbon atoms can be found in branched hydrocarbons but not in linear hydrocarbons. If the hydroxyl carbon of alcohol has a single $R$ group, it is called a primary alcohol. If it has two $R$ groups, it is called a secondary alcohol.