Given below are two statements:
Statement - I: High concentration of strong nucleophilic reagent with secondary alkyl halides which do not have bulky substituents will follow mechanism.
Statement - II: A secondary alkyl halide when treated with a large excess of ethanol follows mechanism.
In the the light of the above statements, choose the most appropriate from the questions given below:
Statement - I: High concentration of strong nucleophilic reagent with secondary alkyl halides which do not have bulky substituents will follow mechanism.
Statement - II: A secondary alkyl halide when treated with a large excess of ethanol follows mechanism.
In the the light of the above statements, choose the most appropriate from the questions given below:
- (A)Statement I is true but Statement II is false.
- (B)Statement I is false but Statement II is true.
- (C)Both statement I and Statement II are false.
- (D)Both statement I and Statement II are true.✓ Correct
Answer: (D)
Solution
The rate law for an substitution is , so the reaction is favoured by a high concentration of a strong nucleophile and by low steric hindrance at the reacting carbon; a secondary substrate without bulky substituents fits both conditions, so Statement I is correct. When the same type of secondary substrate is treated with a large excess of a weak nucleophile in a polar protic solvent such as ethanol, the solvent itself acts as the nucleophile (solvolysis): ionisation to a carbocation, stabilised by solvation from the protic medium, becomes the dominant pathway and the reaction follows , so Statement II is also correct. Both statements are true.
JEE Main · 2024 · 30 Jan 2024 · Shift 2 · Single correct option