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Rapid Review
Definitions of Acid/Base
Acid | Base | |
Bronsted-Lowry | Donates proton | Accepts proton |
Arrhenius | Donates proton | Donates OH- (hydroxyl) group |
Lewis | Accepts electron pair | Donates electron pair |
pH and pOH
pOH = -log10[OH-]
Kw
Kw = [H+] [OH-] =
10-14 (at 25oC)
\
pKw = pH + pOH = 14
\
In neutral water, [H+] = [OH-] =
Ö(10-14) =
10-7
pH = -log10[H+] = 7.0
pOH = -log10[OH-] = 7.0
Ka = [H+] [A-] / [HA]
pKa = -log10Ka
Kb = [HA] [OH-] / [A-]
Note, Ka Kb =
([H+] [A-] / [HA]) x ([HA] [OH-] / [A-])
= [H+] [OH-]
= Kw
= 10-14
And since Ka Kb = 10-14
pKa + pKb = 14 = pKw
A buffer usually consists of: