Question

Which one of the following is correct regarding $S_{N}1$ reaction?

• A. Polar aprotic solvent favour $S_{N}1$ reaction?
• B. Strong nucleophiles are preferred
  
• C. Nucleophile is involved in the RDS.
  
• D. Rate depends on R-X

Answer 1

The correct option is D Rate depends on R-X

Polar protic solvent solvates the halide ion formed due to C-X bond breaking. Therefore, polar protic solvent favours the $S_{N}1$ reaction.

The nucleophile is not involved in the RDS in $S_{N}1$ reaction. thus it does not affect the rate of $S_{N}1$ reaction.
However, a stronger nucleophile may lead to side reactions. So, weak & moderate nucleophiles are preferred.
Rate of the reaction $\propto [R-X{]}^1[Nu{]}^0$
Hence correct option is d.