Mesomeric Effect (+M): How Phenol Releases Electrons

The video tutorial explains the mesomeric effect, a phenomenon where atoms or groups of atoms establish or extend resonance by releasing or withdrawing electrons. It introduces M groups and classifies the mesomeric effect into plus M and minus M effects. The plus M effect is detailed with examples in phenols and vinyl chloride, highlighting how lone electron pairs participate in resonance, increasing electron density and reactivity. The tutorial emphasizes the role of plus M groups in stabilizing molecules and enhancing reactivity in electrophilic aromatic substitution.

What is the primary function of a mesomeric effect in a molecule?

• To increase the molecular weight

• To decrease the boiling point

• To establish or extend resonance

• To change the color of the compound

Which of the following groups is known to exhibit a plus M effect?

• Hydroxyl group

• Nitro group

• Ammonium group

• Carbonyl group

How does the plus M effect influence the reactivity of phenol compared to benzene?

• It makes phenol less reactive

• It makes phenol more reactive

• It has no effect on reactivity

• It makes phenol non-reactive

In the context of the plus M effect, what role does the lone electron pair on chlorine play in vinyl chloride?

• It decreases the electron density

• It participates in resonance

• It increases the molecular size

• It changes the state of matter

What is the result of the lone electron pair on chlorine participating in resonance in vinyl chloride?

• Formation of a new compound

• Increase in molecular weight

• Formation of resonating structures

• Decrease in boiling point