Strength [ENDORSED]

[MichelleT_1L]

What are the best ways to determine strengths of acids and bases when given the molecular formula?

[Emily Glaser 1F]

1. If it's diatomic acid, strength is determined by size, so HCl has a weaker bond than HF since it's a larger atom, so HCl can dissociate better than HF.
2. If it's oxoacid, look at number of O atoms since more electrons are pulled away when there are more O atoms, so HClO3 weaker than HClO4
3. Same O, different element: examine electronegativity of central atom since more electronegative has stronger dipole moment on bond than others, so H will break off better

[diangelosoriano]

Another method is to determine the stability of the conjugate base. If it is a very stable structure, the acid is strong. If the resulting conjugate base has an unstable structure, the acid was weak.

[Justin Lai 1C]

Stronger acids tend to have a greater percent ionization because its conjugate base will tend to stay in that form and be more stable.

[Rummel Requerme 1E]

As stated above, the conjugate base is a good indicator: the more stable it is, the more strong the acid is.

[MinyoungHong_1L]

So, generally speaking, the greater the electronegativity of whatever atom or molecule that the H+ is disassociating from, the stronger the acid due to the increased polarity/ionic character of that compound?