question_answer

Most stable carbanion is:

A)  \[CH_{3}^{-}\]                 

B)  \[C{{H}_{3}}CH_{2}^{-}\]

C)                                 

D)  

Correct Answer: C

Solution :

                 Key Idea: Electron donating groups (e.g., R) increases the electron density and thus make carbanion unstable.  Electron withdrawing groups (e.g.,\[N{{O}_{2}}\]) take away the electrons and thus stabilises the carbanion. \[CH_{3}^{-}\]and\[C{{H}_{3}}\overset{-}{\mathop{C}}\,{{H}_{2}}\]andare unstable due presence of electron withdrawing alkyi group is stabilised by electron withdrawing effect of\[N{{O}_{2}}\]group.