JEE Mains · Chemistry · STD 12 - 6. Haloalkanes and Haloarenes

For the reaction: \(RCH _2 Br + I ^{-} \stackrel{\text { Acetone }}{\longrightarrow} \underset{\text { major }}{ RCH _2 I + Br ^{-}}\) The correct statement is :

A The transition state formed in the above reaction is less polar than the localised anion.
B The reaction can occur in acetic acid also.
C The solvent used in the reaction solvates the ions formed in rate determining step.
D \(Br ^{-}\)can act as competing nucleophile.

Verified Solution

Answer & Solution

Correct Answer

(A) The transition state formed in the above reaction is less polar than the localised anion.

Step-by-step Solution

Detailed explanation

This is finkelstein reaction Clearly, the transition state is less polar than free anions. \(Br ^{-}\)and \(I ^{-}\) Acetic acid is protic which does not support \(S _{ N } 2\) Acetone does not solvate anion \(Br ^{-}\)gets precipitated and hence can not compete with \(I\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Explore more questions on app

From JEE Mains

Explore more questions on app