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. `IgtIIIgtIIgtIV`
B. `IIIgtIVgtIIgtI`
C. `IIgtIgtIIIgtIV`
D. `IVgtIIIgtIIgtI`

Answer

A

Explanation

The order of reactivity in `S_(N)2` reactions is:
`1^(@) gt 2^(@) gt 3^(@)`,
further, amongst `1^(@)` alkyl halides, unsubstituted alkyl halides are more reactive than substituted alkyl hlaides. Thus, the overall decreasing reactivity in `S_(N)2` reaction is:
i.e., `underset(I)(CH_(3)CH_(2)CH_(2)Cl(1^(@))) gt underset(III)((CH_(3))_(2)CHCH_(2)Cl(1^(@))) gt underset(II)(CH_(3)CH_(2)CHClCH_(3)(2^(@))) gt underset(IV)((CH_(3))_(3)C-Cl(3^(@)))`