Assertion : Rate of hydrolysis of methyl chloride to methanol is higher in DMF than in water.
Reason : Hydrolysis of methyl chloride follows second order kinetics.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false

Answer

A

Explanation

Hydrolysis of methyl chloride to methanol follows `S_(N)2` reaction. The rates of many `S_(N)2` reactions are affected by the solvent. Protic solvents-those that contain - OH or- NH group are generally the worst solvents for `S_(N)2`. Polar protic solvents, (like water, alcohols and carboxylic acids), which have strong dipoles but don't have -OH or - NH groups are the best. In contrast to protic solvents, which decrease the rates of `S_(N)2` reactants by lowering the ground state energy of nucleophile, polar aprotic solvents (DMF) increase the rates of `S_(N)2` reactions by raising the ground state energy of nucleophile.