Which of the following would yied a carbanion to the greatest extent on treatment with an alkali?

Options

A. `CH_(3)CHO`
B. `CH_(3)COCH_(2)COCH_(3)`
C. `PhOH`
D. `CH_(3)NO_(2)`

Answer

B

Explanation

The compound has an active methylene group `(-CH_(2)`-group flanked by electron withdrawing groups) and the resulting carbanion is resonance stabilized.

The diketone, pentan `2,4`-dione is about as acidic as phenol, and much more acidic than acetone beacuse the removal of a proton yields a carbanionj that is highly stabilized by accommodation of the `-ve` charge by two oxygens rather than by only one.