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Explain electromeric effect |
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Answer» Solution :Electromeric effect (E) : Electromeric is a temporary effect which operates in unsaturated compounds (containing ` gt C = C lt , gt C = O ` , etc … in the presence of an attacking reagent . Let US consider two DIFFERENT compounds (i) Compounds containing carbonyl group ` ( gt C = O)` : when a nucleophile approaches the carbonyl compound , the `pi` electrons between C and O is instantaneously shifted to the more electronegative oxygen . This makes the carbon electron deficient and thus facilitating the FORMATION of a new bond between the inceoming nuceophile and the carbonyl carbon atom  (ii) Unsaturated compounds such as alkenes ` ( gt C = C lt ) ` : `square ` When an electrophile such as ` H^(+) ` approaches an alkene molecule, the ` pi` electrons are instantaneously shified to the electrophile and a new bond is formed between carbon and hydrogen . This makes the other carbon electron decient and hence it acquires a POSITIVE charge . ` (##SUR_CHE_XI_V02_C12_E01_022_S02.png" width="80%"> ` square ` When the electron is transferred towards the attacking reagnet , it is called + E (positive electromeric ) effect .  ` square` When the ` pi` electron is transfered away from the attacking reagent, it is called , E (negative electromeric ) effect . ` (##SUR_CHE_XI_V02_C12_E01_022_S04.png" width="80%"> |
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