Question

Write a short notes on positive mesomeric effect?

Answer 1

• Positive mesomeric effect occurs, when the electrons move away from substituent attached to the conjugated system. 
• It occurs, if the electron releasing substituents are attached to the conjugated system. 
• The attached group has a tendency to release electrons through resonance, these electron releasing groups are usually denoted as +R or +M groups 
• Examples: -OH, -SH, -OR, -SR, -NH₂ etc.