Question

Explain the terms Inductive and Electromeric effects. Which electron displacement effect explains the following correct orders of acidity of the carboxylic acids? (a) Cl₃CCOOH > Cl₂CHCOOH > ClCH₂COOH (b) CH₃CH₂COOH > (CH₃)₂CHCOOH > (CH₃)₃C.COOH

Accepted Answer

Inductive effect is the permanent polarisation of a covalent bond formed between atoms of different electronegativity, where the electron density shifts towards the more electronegative atom. Electromeric effect is a temporary electron displacement effect that occurs in a molecule when a reagent approaches to attack it, involving the transfer of π-electrons of a multiple bond. The Inductive effect explains the given correct orders of acidity of the carboxylic acids. As stated, electron displacements due to the influence of a substituent group present in the molecule cause permanent polarisation of the bond, which dictates the varying acidity in both (a) and (b). — The textbook context defines the inductive effect as a permanent polarisation caused by substituent groups, while the electromeric effect is a temporary displacement when a reagent attacks. Since the acidity orders depend on the permanent influence of substituents (like Cl or alkyl groups) present in the ground state of the molecule, the inductive effect is responsible for these orders.

Explanation

Apar Academy