Chemistry - GOC Question with Solution | TestHub

In (a) the carbanion is next to the $\mathrm{C}=\mathrm{C}$ that is conjugated with $\mathrm{C}=\mathrm{O}$, so the charge goes on to oxygen. In (b) a $\mathrm{C}{\mathrm{H}}_2$ separates the carbanion from the $\mathrm{C}=\mathrm{C}$, so there is no resonance. a $>$ b.