Question

Which of the following is the functional group of ester?
A.

B.

C.

Answer 1

Hint: Ester is a chemical compound which is formed when the hydroxyl group of acid containing one oxygen atom and one hydrogen atom is replaced by an alkoxy group which contains an oxygen atom bonded to the alkyl group.

Complete step by step answer:

The given functional group is aldehyde in which carbon atom forms four bonds as it is a tetravalent compound. One oxygen atom is attached to a central carbon atom by a double bond, one hydrogen atom is attached to a central carbon atom by a single bond and one alkyl or aryl group is attached to the central carbon atom by a single bond. The aldehyde functional group is represented by –CHO. The suffix used for the functional group aldehyde is –al.

The given functional group is ester in which the carbon atom forms four bonds as it is a tetravalent compound. One oxygen atom is attached to a central carbon atom by a double bond, one alkoxy group is attached to a central carbon atom by a single bond and one alkyl or aryl group is attached to the central carbon atom by a single bond. The ester functional group is represented by –COOR. The suffix used for the functional ester is –oate.

The given functional group is carboxylic acid in which carbon atom forms four bonds as it is a tetravalent compound. One oxygen atom is attached to a central carbon atom by a double bond, one hydroxyl group is attached to a central carbon atom by a single bond and one alkyl or aryl group is attached to the central carbon atom by a single bond. The carboxylic acid functional group is represented by –COOH. The suffix used for the functional group is –oic acid.
So, the correct answer is “Option B”.

Note:
Esters are also obtained from inorganic acids like phosphate ester is formed from phosphoric acid, sulfate ester is formed from sulfuric acid.