Question

Explain positive and negative resonance effect

Answer 1

Positive resonance or mesomericeffect (+M or +R): The groups showpositive mesomeric effect when they release electrons to the rest of the molecule by delocalization. These groups are denoted by +M or +R. Due to this effect, the electron density on rest of the molecular entity is increased.

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Answer 2

Answer:

the group's are usually donated by _R or _m