How can you tell NH3 is a better base than HOCOO-? I look at the conjugate species in both to determine their relative stabilities. Where NH4+ is the conjugate acid of ammonia and HOCOOH the conjugate acid for acetate. In this case, isn't the NH3 more stable than NH4+ since it is uncharged yet still has a full octet on the N? Also, wouldn't the HOCOOH be more stable than HOCOO- since it's not charged and thus doesn't even have any charge to spread. Therefore, using this reasoning of the actual charges, should HOCOO- be the better base since its conjugate acid is more stable (lower in energy; it is weaker than NH4+)? I'm sure there are other properties like the electronegativity of the atom bearing the charge, atomic size, electron withdrawing atoms in the compounds and net charge, but how do you determine the priority when comparing compounds like this? Are there any other properties I'm missing?