Question

In which of the following reaction intermediate do not form?

• A. $S_{N}2$
• B. $S_{N}1$
• C. (a) and (b) above.
• D. None of the above

Answer 1

The correct option is A $S_{N}2$

In $S_{N}2$ reaction, pentavalent unstable transition state forms in which nucleophile is forming bond with carbon simultaneously while leaving group is breaking its bond. It is a single step reaction.

In $S_{N}1$ reaction, carbocation is formed as a intermediate.