Question

Which one of the following is excellent
substrate for SN2 reaction?
A) CH3-X
(B) R-C-Ch2-X
(C) Ar-CH2-X
(D) CH2=CH-CH2-X​

Answer 1

Answer:

A

Explanation:

Answer 2

$CH_{3} -X$ is an excellent substrate for $SN_{2}$ reaction among the given options.

• $SN_{2}$ reaction is a substitution nucleophilic reaction in which the nucleophile attacks the carbon atom from the backside.
• So the steric hindrance is the major factor that must be considered in   $SN_{2}$ reaction.
• To avoid steric hindrance, the substituents on carbon, on which the substitution must occur, must be less bulky.
• In $R-C-CH_{2} -X$, the carbon has two hydrogens and one $-CH_{2} R$ group.
• In $Ar-CH_{2} -X$, the carbon has two hydrogens and one $-Ar$ group.
• In $CH_{2} =CH-CH_{2} -X$, the carbon has two hydrogens and one $-CH=CH_{2}$ group.
• In $CH_{3} -X$, the carbon has three hydrogens as substituents.
• Thus the less crowded carbon is present in $CH_{3} -X$.