question_answer

Arrange the following in decreasing order of their reactivity toward S^ reaction. 1. \[M{{e}_{3}}C{{O}^{-}}\]                          2. \[Me{{O}^{-}}\] 3. \[MeC{{H}_{2}}{{O}^{-}}\]                       4. \[M{{e}_{2}}CH{{O}^{-}}\] 5.

A)  2 > 3 > 5 > 4 > 1     

B)  5 > 3 > 2 > 1 > 4       

C)  1 > 5 > 2 > 3 > 4     

D)  3 > 5 > 1 > 2 > 3

Correct Answer: A

Solution :

 Idea This problem includes conceptual mixing of \[{{S}_{N}}^{2}\] reaction and nucleophilicity of reagent. Students are advised to use the concept   of   steric   hindrance   and nucleophilicity of species to answer the question. The reagent having greater value of nucleophilic character undergo faster nucleophilic substitution reaction. Steric hindrance play an important role according to which greater the steric hindrance lower the reactivity towards\[{{S}_{{{N}^{2}}}}\]. Test Edge Students are advised to study the effect of different substrate, solvent in \[{{S}_{N}}2\] reaction which is asked generally.