Question

Which one of the following solvents favors $S_{N}2$ reaction?

• A. 1 & 3
• B. 1 & 2
• C. 1 & 4
• D. All four

Answer 1

The correct option is A 1 & 3

Polar aprotic solvent favours $S_{N}2$ reaction because polar aprotic solvent is unable to solvate the nucleophile due to this nucleophilicity of a nucleophile does not decrease in such solvent. Both DMSO and acetone are polar aprotic solvent hence they favour $S_{N}2$ reaction.
Ethanol and water are polar protic solvent and hence both favours $S_{N}1$ reaction.