By use of a new keyword - "pKa" - the pKa of the most readily ionized hydrogen atoms attached to oxygen atoms will be printed. The pKa calculation uses the charge on the hydrogen and the O-H bond-length, and for a set of simple organic compounds has the following accuracy:
| Average signed error: | -0.02 |
| Median error | 0.21 |
| Average unsigned error: | 0.31 |
| Root mean square error: | 0.43 |

Individual Species used in Preparing this Graph
|
Molecule |
Exp. pKa |
Calc'd pKa |
Diff. |
|Diff.| |
(Diff.)^2 |
|
1-Naphthoic acid |
3.69 |
4.35 |
0.66 |
0.66 |
0.43 |
|
2,2,2-Trichloroethanol |
12.02 |
12.22 |
0.20 |
0.20 |
0.04 |
|
2,2,2-Trifluoroethanol |
12.40 |
12.27 |
-0.13 |
0.13 |
0.02 |
|
2,2-Dimethylpropionic acid |
5.03 |
5.23 |
0.20 |
0.20 |
0.04 |
|
2,3,4,6-Tetrachlorophenol |
5.62 |
6.08 |
0.46 |
0.46 |
0.21 |
|
2,3,4-Trichlorophenol |
7.10 |
7.17 |
0.07 |
0.07 |
0.00 |
|
2,3-Dichlorophenol |
7.76 |
7.81 |
0.05 |
0.05 |
0.00 |
|
2,4,5-Trichlorophenol |
7.07 |
7.02 |
-0.05 |
0.05 |
0.00 |
|
2,4,6-Trichlorophenol |
6.21 |
6.30 |
0.09 |
0.09 |
0.01 |
|
2,4,6-Trinitrophenol |
0.60 |
0.54 |
-0.06 |
0.06 |
0.00 |
|
2,4-Dichlorophenol |
8.09 |
7.40 |
-0.69 |
0.69 |
0.48 |
|
2,5-Dichlorophenol |
7.51 |
7.62 |
0.11 |
0.11 |
0.01 |
|
2,6-Dichlorophenol |
6.79 |
7.03 |
0.24 |
0.24 |
0.06 |
|
2-Chlorobutanoic acid |
2.86 |
2.72 |
-0.14 |
0.14 |
0.02 |
|
2-Chlorophenol |
8.29 |
8.22 |
-0.07 |
0.07 |
0.01 |
|
2-Chloropropanoic acid |
2.83 |
2.93 |
0.10 |
0.10 |
0.01 |
|
2-Hydroxypropanoic acid |
3.86 |
3.31 |
-0.55 |
0.55 |
0.30 |
|
2-Naphthoic acid |
4.17 |
4.23 |
0.06 |
0.06 |
0.00 |
|
3,4-Dichlorophenol |
8.68 |
8.31 |
-0.37 |
0.37 |
0.13 |
|
3,5-Dichlorophenol |
8.27 |
8.33 |
0.06 |
0.06 |
0.00 |
|
3-Chlorobutanoic acid |
4.05 |
4.28 |
0.23 |
0.23 |
0.05 |
|
3-Chlorophenol |
8.78 |
8.96 |
0.18 |
0.18 |
0.03 |
|
3-Chloropropanoic acid |
3.98 |
4.29 |
0.31 |
0.31 |
0.10 |
|
4-Chlorobutanoic acid |
4.53 |
4.71 |
0.18 |
0.18 |
0.03 |
|
4-Chlorophenol |
9.14 |
8.81 |
-0.33 |
0.33 |
0.11 |
|
Acetic acid |
4.76 |
5.00 |
0.24 |
0.24 |
0.06 |
|
Acrylic acid |
4.25 |
4.65 |
0.40 |
0.40 |
0.16 |
|
Alanine |
2.35 |
2.36 |
0.01 |
0.01 |
0.00 |
|
Argenine |
2.35 |
2.34 |
-0.01 |
0.01 |
0.00 |
|
Ascorbic acid |
4.17 |
2.64 |
-1.53 |
1.53 |
2.35 |
|
Asparagine |
2.01 |
2.02 |
0.01 |
0.01 |
0.00 |
|
Aspartic acid |
2.10 |
1.98 |
-0.12 |
0.12 |
0.01 |
|
Benzohydroxamic acid |
8.88 |
8.89 |
0.01 |
0.01 |
0.00 |
|
Benzoic acid |
4.20 |
4.30 |
0.10 |
0.10 |
0.01 |
|
Benzophenone oxime |
11.30 |
11.18 |
-0.12 |
0.12 |
0.01 |
|
Bromoacetic acid |
2.86 |
3.11 |
0.25 |
0.25 |
0.06 |
|
Butanoic acid |
4.82 |
4.78 |
-0.04 |
0.04 |
0.00 |
|
Chloroacetic acid |
2.86 |
4.18 |
1.32 |
1.32 |
1.74 |
|
Citric acid |
3.13 |
2.56 |
-0.57 |
0.57 |
0.32 |
|
Cyanoacetic acid |
2.43 |
1.74 |
-0.69 |
0.69 |
0.47 |
|
Cysteine |
2.05 |
1.42 |
-0.63 |
0.63 |
0.40 |
|
Dichloroacetic acid |
1.26 |
1.42 |
0.16 |
0.16 |
0.02 |
|
Ethanol |
16.00 |
16.37 |
0.37 |
0.37 |
0.14 |
|
Fluoroacetic acid |
2.66 |
2.96 |
0.30 |
0.30 |
0.09 |
|
Formic acid |
3.77 |
3.77 |
0.00 |
0.00 |
0.00 |
|
Fumaric acid |
3.02 |
3.22 |
0.20 |
0.20 |
0.04 |
|
Glutamic acid |
2.10 |
2.01 |
-0.09 |
0.09 |
0.01 |
|
Glutamine |
2.17 |
2.49 |
0.32 |
0.32 |
0.10 |
|
Glycine |
2.35 |
2.53 |
0.18 |
0.18 |
0.03 |
|
Histidine |
1.77 |
1.98 |
0.21 |
0.21 |
0.04 |
|
Iodoacetic acid |
3.12 |
3.30 |
0.18 |
0.18 |
0.03 |
|
Isoleucine |
2.32 |
2.48 |
0.16 |
0.16 |
0.02 |
|
Isophthalic acid |
3.46 |
3.50 |
0.04 |
0.04 |
0.00 |
|
Leucine |
2.33 |
2.38 |
0.05 |
0.05 |
0.00 |
|
Lysine |
2.18 |
2.53 |
0.35 |
0.35 |
0.12 |
|
m-Chlorobenzoic acid |
3.82 |
3.80 |
-0.02 |
0.02 |
0.00 |
|
m-Chlorophenol |
9.02 |
8.99 |
-0.03 |
0.03 |
0.00 |
|
m-Cresol |
10.08 |
9.63 |
-0.45 |
0.45 |
0.21 |
|
m-Hydoxybenzoic acid |
4.08 |
4.03 |
-0.05 |
0.05 |
0.00 |
|
m-Hydroxyaniline |
9.87 |
9.11 |
-0.76 |
0.76 |
0.58 |
|
m-Hydroxybenzaldehyde |
8.00 |
9.34 |
1.34 |
1.34 |
1.80 |
|
m-Methoxybenzoic acid |
4.09 |
4.07 |
-0.02 |
0.02 |
0.00 |
|
m-Methoxyphenol |
9.66 |
9.06 |
-0.60 |
0.60 |
0.36 |
|
m-Methylbenzoic acid |
4.27 |
4.41 |
0.14 |
0.14 |
0.02 |
|
m-Methylphenol |
10.08 |
9.77 |
-0.31 |
0.31 |
0.10 |
|
m-Nitrobenzoic acid |
3.49 |
3.19 |
-0.30 |
0.30 |
0.09 |
|
m-Nitrophenol |
8.39 |
7.75 |
-0.64 |
0.64 |
0.41 |
|
Malaic acid |
1.93 |
1.81 |
-0.12 |
0.12 |
0.01 |
|
Methanol |
15.54 |
15.23 |
-0.32 |
0.32 |
0.10 |
|
Methionine |
2.28 |
2.30 |
0.02 |
0.02 |
0.00 |
|
n-Pentanoic acid |
4.82 |
4.77 |
-0.06 |
0.06 |
0.00 |
|
o-Cresol |
10.28 |
11.17 |
0.89 |
0.89 |
0.80 |
|
o-Hydroxyaniline |
9.71 |
9.08 |
-0.63 |
0.63 |
0.39 |
|
o-Hydroxybenzaldehyde |
6.79 |
7.54 |
0.75 |
0.75 |
0.57 |
|
o-Nitrophenol |
7.17 |
7.52 |
0.35 |
0.35 |
0.12 |
|
Oxalic acid |
1.23 |
1.60 |
0.37 |
0.37 |
0.13 |
|
p-Aminophenol |
10.46 |
9.85 |
-0.61 |
0.61 |
0.37 |
|
p-bromobenzoic acid |
4.00 |
3.61 |
-0.39 |
0.39 |
0.15 |
|
p-Bromophenol |
9.35 |
8.72 |
-0.63 |
0.63 |
0.40 |
|
p-Chlorobenzoic acid |
3.99 |
3.99 |
0.00 |
0.00 |
0.00 |
|
p-Chlorophenol |
9.38 |
8.82 |
-0.56 |
0.56 |
0.31 |
|
p-Cresol |
10.19 |
10.27 |
0.08 |
0.08 |
0.01 |
|
p-Hydoxybenzoic acid |
4.59 |
4.63 |
0.04 |
0.04 |
0.00 |
|
p-Hydroxyaniline |
10.30 |
10.41 |
0.11 |
0.11 |
0.01 |
|
p-Hydroxybenzaldehyde |
7.66 |
8.09 |
0.43 |
0.43 |
0.18 |
|
p-Iodophenol |
9.30 |
8.67 |
-0.63 |
0.63 |
0.40 |
|
p-Methoxybenzoic acid |
4.48 |
4.82 |
0.34 |
0.34 |
0.11 |
|
p-Methoxyphenol |
10.21 |
10.63 |
0.42 |
0.42 |
0.17 |
|
p-Methylbenzoic acid |
4.38 |
4.66 |
0.28 |
0.28 |
0.08 |
|
p-Methylphenol |
10.17 |
10.29 |
0.12 |
0.12 |
0.01 |
|
p-Nitrobenzoic acid |
3.49 |
2.95 |
-0.55 |
0.55 |
0.30 |
|
p-Nitrophenol |
7.15 |
7.29 |
0.14 |
0.14 |
0.02 |
|
Pentachlorophenol |
4.90 |
5.55 |
0.65 |
0.65 |
0.42 |
|
Phenol |
10.00 |
9.71 |
-0.29 |
0.29 |
0.09 |
|
Phenylalanine |
2.58 |
2.01 |
-0.57 |
0.57 |
0.33 |
|
Phthalic acid |
2.98 |
2.40 |
-0.58 |
0.58 |
0.33 |
|
Proline |
2.00 |
2.36 |
0.36 |
0.36 |
0.13 |
|
Propionic acid |
4.88 |
4.91 |
0.03 |
0.03 |
0.00 |
|
Pyruvic acid |
2.50 |
2.85 |
0.35 |
0.35 |
0.12 |
|
Serine |
2.21 |
1.86 |
-0.35 |
0.35 |
0.12 |
|
t-Butanol |
17.00 |
16.25 |
-0.75 |
0.75 |
0.56 |
|
Terephthalic acid |
3.51 |
3.59 |
0.08 |
0.08 |
0.01 |
|
Threonine |
2.09 |
1.95 |
-0.14 |
0.14 |
0.02 |
|
Trichloroacetic acid |
0.63 |
-0.40 |
-1.03 |
1.03 |
1.06 |
|
Trifluoroacetic acid |
0.00 |
-0.18 |
-0.18 |
0.18 |
0.03 |
|
Tryptophan |
2.38 |
2.39 |
0.01 |
0.01 |
0.00 |
|
Tyrosine |
2.20 |
2.43 |
0.23 |
0.23 |
0.05 |
|
Valine |
2.29 |
2.61 |
0.32 |
0.32 |
0.10 |
|
Water |
15.74 |
15.75 |
0.01 |
0.01 |
0.00 |