Which among the following is a feature of $S_N 1$ mechanism?
Which among the following is a feature of $S_N 1$ mechanism?
Single step mechanism
Only backside attack of nucleophile
Transition state contains pentacoordinate carbon
Formation of planar carbocation intermediate
Solution
The $\mathrm{S}_{\mathrm{N}} 1$ reaction is a nucleophilic substitution reaction where the rate-determining step is unimolecular. It is a type of organic substitution reaction. $\mathrm{S}_N$ l stands for substitution nucleophilic unimolecular. Thus, the rate equation (which states that the $\mathrm{S}_{\mathrm{N}} 1$ reaction is dependent on the electrophile but not on the nucleophile) holds in situations where the amount of the nucleophile is far greater than the amount of the carbocation intermediate.
This reaction involves the formation of a carbocation intermediate. It is generally seen in the reactions of tertiary or secondary alkyl halides with secondary or tertiary alcohols under strongly acidic or strongly basic conditions. The $\mathrm{S}_{\mathrm{N}}$ l reaction is often referred to as the dissociative mechanism in inorganic chemistry. Given below are some examples of an $\mathrm{S}_N 1$ type of nucleophilic substitution reaction.