Arrange the following carbanions in order of their decreasing stability.
A) `H_(3)C-C-=C^(-)`
B) `H-C-=C^(-)`
C) `H_(3)C-Cbar(H)_(2)`

Options

A. `A gt B gt C`
B. `B gt A gt C`
C. `C gt B gt A`
D. `C gt A gt B`

Answer

B

Explanation

`+` I-effect decreases the stability of carbon anion. Since, `(CH_3)`group has + I-effect, therefore, it intensifies the negatives charge and hence destabilises (A) relative to (B). sp hybridised carbanion is more stabilised than `sp^3`
`{:(CH -=C^(-) gt CH_(3)-C -= C^(-) gt CH_(3) - CH_(2)),(" "(B)^(sp)" "(A)^(sp)" " (C)" "sp^(3)):}`
Hence, `B gt A gt C`