Anions of Weak Acids as Weak Bases
A-(aq) + H2O(l) HA(aq) + OH-(aq)
F-(aq) + H2O(l) HF(aq) + OH-(aq)
Kb = ([HF][OH-]) / [F-]
Rationale for the basicity of A-(aq): e.g., 1 M NaF
Acidity is determined by [OH-] generated from the F- reaction and
[H3O+] generated from the auto-ionization of water; since
[OH-] >> [H3O+], the solution is basic.
Ka x Kb = Kw
For a conjugate acid-base pair:
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