Question

Tertiary alkyl halides are practically inert to sutstitution by $S_{N}2$ mechanism because:

• A. insolubility
• B. instabilty
• C. steric hinderance
• D. inductive effect

Answer 1

The correct option is C steric hinderance

In a $S{N}_2$ reaction, there will be five groups attached to the carbon atom at which reaction occurs. This happened during a transition state. Thus, there will be crowding during this stage, & due to the presence of bulky groups make the reaction sterically hindered

$\therefore$ Tertiary alkyl halides are practically inert to substitution by $SN2$ mechanism because of the steric hindrance.

Option C is correct.