12.17. Explain the terms Inductive and Electromeric effects. Which electron displacement effect explains the following correct orders of acidity of the carboxylic acids?
Inductive effect- The permanent displacement of sigma () electrons along the saturated chain, whenever an electron donating or withdrawing group is present, is known as the inductive effect. It could be effect.
Electromeric effect- The complete transfer of the shared pair of -electrons to one of the atoms linked by multiple bonds on the demand of attacking reagent. It is a temporary effect. It may be +E(electrons transferred towards attacking reagent) or -E effect(electron transferring away from the attacking reagent).
(a) The order of acidity can be explained by the negative inductive effect (). As the no. of chlorine atom increases, the effect also increases and so, the acidic strength also increases.
(b) This can be explained by the effect of the alkyl group. As the number of electron donor group increases, effect will also increase. With the increases in effect, the acidic character decreases accordingly.