Question

Why is \[ - COOH\] electron withdrawing?

Answer 1

Hint: The general formula of a carboxylic acid is \[R - COOH\] in which \[COOH\] refers to the carboxyl group and \[R\] refers to the rest of the molecule to which the carboxyl group is attached. In this group, a carbon shares a double bond with oxygen and a single bond with the hydroxyl group.

Complete answer:
The given formula \[ - COOH\] in the question is of carboxylic acids. The general formula for a carboxylic acid is \[R - COOH\] in which \[COOH\] refers to the carboxyl group and \[R\] refers to the alkyl or aryl group. A carboxylic acid is an organic compound which contains a carboxyl group that acts as a functional group. It is the most important functional group that contains carbonyl group \[(C = O)\]
The carbon in the carboxyl group is attached to oxygen with a double bond and to hydroxyl group with a single bond. Example of carboxylic acids are- Methanoic acids \[(HCOOH)\] , also known as formic acid, ethanoic acid \[(C{H_3}COOH)\] and propanoic acid \[(C{H_3}C{H_2}COOH)\] etc.
Carboxyl group \[ - COOH\] is an electron withdrawing group as it contains a hydroxyl group attached to carbonyl carbon. Due to the electronegativity of the oxygen atom, this functional group undergoes ionization and discharges a proton. It forms a more stable anion as it stabilizes by the presence of two oxygen atoms. Hence, it acts as a better acid than the equivalent alcohol.
For example – Electrophilic substitution does not take place readily for benzene. The incoming individual will join the carboxyl group at Meta position rather than at ortho and para position. Hence, the carboxyl group acts as a deactivating group.

Note:
Carboxylic acids are widely occurring in nature and it can be synthesized in the laboratories. This organic compound can be found as in food products such as citric acid in lemons, lactic acids in milk and Butyric acid in butter etc. the carboxylate anion obtained by deprotonation of carboxylic acids with the formula \[R - CO{O^ - }\] can be used in making variety of salts such as soaps.