Question

\(S_N1\) reactions are generally carried out in which type of solvents?

• A. Polar aprotic solvent
• B. Non-polar aprotic solvent
• C. Polar protic solvent
• D. Non-polar protic solvent

Hint:

Remember: \[ S_N1 \rightarrow \text{Polar protic solvent} \] \[ S_N2 \rightarrow \text{Polar aprotic solvent} \] Polar protic solvents stabilize carbocations and thus favor the \(S_N1\) mechanism.

Answer 1

The Correct Option is C

Step 1: Recall the S\(_N\)1 mechanism.
The rate-determining step in S\(_N\)1 is ionisation of the substrate to form a carbocation. This step requires stabilisation of both the carbocation intermediate and the leaving group anion.

Step 2: Match the solvent requirement.
Polar protic solvents (e.g., water, alcohols) stabilise ions by hydrogen bonding and electrostatic solvation -- they are ideal for S\(_N\)1. Polar aprotic solvents favour S\(_N\)2 instead. \[ oxed{ ext{Polar protic solvent}} \]