question_answer

The temporary effect in which there is complete transfer of a shared pair of pi-electrons to one of the atoms joined by a multiple bond on the demand of an attacking reagent is called

A)  inductive effect

B)  positive resonance effect

C)  negative resonance effect

D)  hyperconjugation

E)  electromeric effect

Correct Answer: E

Solution :

Electromeric effect involves the complete transfer of electrons of a multiple bond (double or triple bond) to one of the bonded atoms (usually more electronegative) in presence of an attacking reagent. This effect is temporary and takes place only in the presence of a reagent. As soon as the reagent is removed, the molecule reverts back to its original position.