Question

Which of the following is/are correct regarding $E_2$ elimination of alkyl halides?

• A. It is favoured by polar protic solvents.
• B. It is favoured by polar aprotic solvents.
• C. Solvation of base and leaving group do not take place by polar aprotic solvent.
• D. Both (b) and (c)

Answer 1

The correct option is D Both (b) and (c)

$E_2$ elimination is favoured by a polar aprotic solvents like DMSO, acetone etc.
Solvation of base and leaving group do not take place.
However, the polar aprotic solvent cannot form hydrogen bonds. Also, because their positive centres are well-shielded by steric effects from any interaction with anions, the polar aprotic solvent does not solvate anions to any appreciable extent.
Moreover, the partial positive charge of sulfur is decreased due to the +I effect of methyl groups around it.



Since the base remains unsolvated, it readily attacks the proton.