Question

The fruity smell is of a/an:
(a) aldehyde
(b) ketone
(c) alcohol
(d) ester

Answer 1

Hint: To know which of the following groups gives a fruity smell, we should know about their physical properties like whether they are colored or colorless, have pungent, suffocating ,fruity or no smell , solubility, boiling point etc.

Complete answer:
By knowing the physical properties of aldehydes, ketones ,alcohols and ester, we can easily identify the functional group which gives the fruity smell.
Let’s discuss their physical properties in the tabular form through which it is easy to understand them.

Sr. no	Functional group	Physical properties
		color	smell	Boilingpoint	solubility
1.	Aldehyde	colorless	The lower aldehydes have unpleasant odour while the higher aldehydes have pleasant odour.	Have high boiling point than the hydrocarbons but lower than the alcohols and carboxylic acids.	Solubility decreases with increase in the molecular mass.
2.	Ketone	colorless	Pleasant odour	Have a higher boiling point than the aldehydes but lower than the alcohols and carboxylic acids.	Solubility decreases with increase in the molecular mass.
3.	Alcohol	colorless	Lower alcohols have characteristic smell but the higher alcohols are odorless	Lower alcohols have low boiling point but higher alcohols have high boiling point.	Soluble
4.	Ester	colorless	Fruity smell	Have lower boiling point than the corresponding parent acids.	Sparingly soluble in the water.

So, thus from this table it's clear that the functional group which has a fruity smell is ester.

Hence, option (d) is correct.

Note: Ester are the compounds which are formed from the carboxylic acids by the replacement of the -OH group i.e. hydroxyl group in carboxylic acid by the -O-R group i.e. the alkoxy group these are the organic compounds and are quickly react with the water to form alcohols and acids.