question_answer 1)

  Arrange the following carbanions in order of their decreasing stability : (A) \[{{H}_{3}}C-C\equiv {{C}^{-}}\]         (B) \[H-C\equiv {{C}^{-}}\]                           (C) \[{{H}_{3}}C-CH_{2}^{-}\] (a) \[A\text{ }>B>C~\]                   (b)\[B>A>C\]                     (c) \[C\text{ }>\text{ }B\text{ }>\text{ }A\]          (d) \[C>A>B\]

Answer:

  (b) sp-Hybridized carbon is more electronegative than a \[s{{p}^{3}}\]-hybridized carbon, therefore (A) and (B) are more stable than (C) Since \[C{{H}_{3}}\] group has \[+I\] effect and hence it intensified the negative charge and so, destabilised (A) as compared to (B)