Final answer:
Carbanion stability increases from primary to tertiary, affected by factors like resonance stabilization, bond strengths, and inductive effects.
Step-by-step explanation:
The stability of carbanions increases in the order of primary (RCH₂) < secondary (R₂CH) < tertiary (R₃C). Stability is influenced by resonance stabilization, where greater resonance leads to greater stability. The carbonate ion is an excellent example, as it has three equivalent resonance structures, showing how resonance can stabilize a conjugate base. Furthermore, the stability of the conjugate base, relative bond strengths, and inductive effects are factors used to predict the increasing tendency of a compound to ionize in an aqueous solution. For carbanions, a more substituted carbanion is less stable due to increased electron density and higher associated strain.