Question

Ethanol is more reactive than acetone towards nucleophilic addition reaction

Answer 1

Aldehydes and ketones contain carbonyl group,which is highly polar due to difference in electronegativity of carbon and oxygen.Hence aldehydes and ketone both give nucleophilic addition reaction.

Ethanal is an aldehyde containing two carbon atoms.In case of ehanal (aldehyde), one methyl group (alkyl group)is attached to the carbonyl group.Methyl group is +I group,so it tend to decrease the magnitude of charge on carbonyl carbon of aldehyde.As just one such alkyl group is present in case of aldehydes, nucleophilic attack is more facillitated comparatively.

Answer 2

Ethanal is aldehyde where as acetone is dimethyl ketone. Aldehyde always is more reactive than ketone towards nucleophilic addition reaction.It can be explained on the basis of electronic as well as steric factor.

In case of acetone, its is due to presence of two methyl groups, the nucleophile has lesser tendency to attack at the carbonyl centre.The steric hindrance in acetaldehyde is less.

On the other hand the +I effect of two methyl groups decrease the deficiency of carbonyl carbon of acetone. Hence the nucleophile has lesser tendency to attack at the carbonyl centre.