Question

Alcohols are weak electrophiles and poor leaving groups; therefore, a nucleophile is unlikely to displace the hydroxyl group (-OH) of an alcohol. To improve its leaving group ability, an alcohol can be converted into a ________ or a ________.

1) carbocation
2) alkyl halide
3) ester
4) ketone

Answer 1

Alcohols can be converted into better leaving groups by transforming them into alkyl halides or esters, enabling nucleophilic substitution reactions.

Step-by-step explanation:

To improve the leaving group ability of an alcohol, an alcohol can be converted into an alkyl halide or an ester. Alcohols are weak electrophiles and have poor leaving groups because the hydroxyl (-OH) group is strongly bonded to the carbon atom and is not easily displaced by a nucleophile. When the alcohol reacts with a strong acid, the -OH is protonated, forming water, which is a much better leaving group. This conversion allows subsequent nucleophilic substitution reactions to take place.

For instance, treating an alcohol with hydrohalic acids such as HCl, HBr, or HI can lead to the formation of an alkyl halide, where the halide (Cl, Br, or I) replaces the hydroxyl group. On the other hand, reaction with a carboxylic acid or its derivatives can transform an alcohol into an ester, where the hydroxyl group is replaced by an alkoxy group. Both of these derivatives are more reactive towards nucleophilic substitution than the original alcohol.