Question

How does inductive effect influence the reactivity and acidity of carboxylic acids?

Answer 1

(a) Reactivity: 

• When a highly electronegative atom such as halogen is attached to a carbon then it makes the C—X bond polar. 
• In such cases the -I effect of halogen facilitates the attack of an incoming nucleophile at the polarized carbon and hence increases the reactivity.

 

• If a -I group is attacher neared to a carbonyl carbon, it decreases the availability of electron density on the carbonyl carbon and hence increases the rate of the nucleophilic addition reaction.

 (b) Acidity of carboxylic acid:

• When a halogen atom is attached to the carbon which is neared to the carboxylic acid group, its -I effect withdraws the bonded electrons towards itself and makes the ionization of H+ easy. 
• The acidity of various chioro acetic acid is in the following order. Cl₃C-COOH > Cl₂CHCOOH > ClCH₂COOH The strength of the acid increases with increase in the effect of the group attached to the carboxyl group. 
• Similarly the following order of acidity in the carboxylic acids is due to the +1 effect of alkyl group. (CH₃)₃CCOOH < (CH₃)₂CHCOOH< CH₃COOH