Question

Which of the following represents an ester?

• A. CH$_3$ - O - CH$_3$
• B. CH$_3$ - O - CH$_2$
• C. CH$_3$ - C - H
• D. CH$_3$ - C = O

Hint:

Ester structures typically have the functional group -COO-, where a carbonyl group (C=O) is bonded to an oxygen atom which is also bonded to an alkyl group.

Answer 1

The Correct Option is A

An ester is a compound derived from an acid (often a carboxylic acid) and an alcohol. The general formula for an ester is RCOOR', where R and R' are alkyl or aryl groups. In the given options: - Option (a) shows the structure CH$_3$ - O - CH$_3$, which corresponds to methyl ether, an example of an ester. - Option (b) shows a different structure, not fitting the ester formula. - Option (c) and (d) are aldehydes or ketones, not esters. Therefore, the correct answer is (a).