Question

The correct order of leaving group ability in a nucleophilic substitution reaction is

• A. $Br ^{-}> Cl ^{-}> CH _{3} CO _{2}^{-}> HO ^{-}> H ^{-}$
• B. $H ^{-}> OH ^{-}> CH _{3} CO _{2}^{-}> Cl ^{-}> Br ^{-}$
• C. $Br ^{-} CH _{3} CO _{2}^{-} Cl ^{-}> OH ^{-}> H ^{-}$
• D. $CH _{3} CO _{2}^{-}> Br ^{-}> Cl ^{-}> OH ^{-}> H ^{-}$

Answer 1

Answer: (A)

The correct order of leaving group ability in a nucleophilic substitution reaction is
$Br ^{-}> Cl ^{-}> CH _{3} COO ^{-}> HO ^{-} H ^{-}$
Because the best leaving group is that which is conjugal base of strong acid.