Acid equilibrium constants
acid
pKa
Ka
Methanoic acid
3.75
1.78 x 10-4
Ethanoic acid
4.75
1.78 x 10-5
Propanoic acid
4.90
1.26 x 10-5
Butanoic acid
4.82
1.51 x 10-5
Pentanoic acid
4.84
1.45 x 10-5
Benzene carboxylic acid
4.20
6.30 x 10-5
Phenol
9.89
1.29 x 10-10
Hydrocyanic acid
9.40
3.98 x 10-10
Nitrous acid
3.34
4.57 x 10-4
Chloroethanoic acid
2.86
1.38 x 10-3
Dichloroethanoic acid
0.66
2.20 x 10-1
Trichloroethanoic acid
1.29
5.10 x 10-2
Carbonic acid
6.40
3.98 x 10-7
Base equilibrium constants
Base
pKa
Ka
Ammonia
9.25
5.62 x 10-10
Pyridine
8.74
1.82 x 10-9
Phenol
9.89
1.29 x 10-10
Phenylmethylamine
9.37
4.27 x 10-10
Trimethylamine
9.80
1.58 x 10-10
Methylamine
10.65
2.24 x 10-11
Dimethylamine
10.77
1.70 x 10-11
Phenylamine
9.38
4.17 x 10-10