Question

Assertion (A): In $S_N1$ reaction racemic mixture is formed and in $S_N2$ reaction inversion of configuration is observed. Reason (R): $S_N1$ reaction is concerted mechanism and $S_N2$ reaction involves carbocation intermediate.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

$S_N\textbf{1}$ = 1 intermediate (carbocation). $S_N\textbf{2}$ = 2 species in a single step (concerted).

Answer 1

The Correct Option is C

Step 1: Concept $S_N1$ involves a two-step mechanism with a planar carbocation, allowing attack from both sides (racemization).

Step 2: Meaning $S_N2$ is a single-step, concerted mechanism where the nucleophile attacks from the backside (Walden inversion).

Step 3: Analysis Assertion (A) correctly describes the stereochemical outcomes of both reactions. However, Reason (R) is factually incorrect because it swaps the mechanisms: $S_N1$ uses a carbocation and $S_N2$ is concerted.

Step 4: Conclusion Since the Assertion is true but the Reason is false, the correct option is 3. Final Answer: (3)