Question

+ M effect is observed in
1. CH2=CH-Br
2. CH2=CH-CH=CH-N
3. CH3-CH=CH2
4. CH2=CH-CN​

Answer 1

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Answer 2

Answer:

The mesomeric effect is negative (–M) when the substituent is an electron-withdrawing group and the effect is positive (+M) when the substituent is an electron releasing group. The net electron flow from or to the substituent is determined also by the inductive effect.