[smghz]

Is there a particular rule that is helpful in determining which ketone among a list of ketones is the least or most acidic without using a pKa chart? Is resonance stabilization and/or number of hydrogens present involved? thanks

[clarkstill]

Stability of the conjugate base. I.e. for:

AH  A- + H+

Substituents that stabilize the enolate A- (e.g. electronegative atoms, further conjugation, etc.) mean that the equilibrium lies further to the right, so AH is by definition a stronger acid.

The converse is true for groups that destabilize the enolate.

Hope that makes sense.