pH of Organic Acids and Salts

Based on given acidity constants (pKa values) the pH of organic acids for 1, 10, and 100 mmol/L are calculated. The results are listed in the following tables (valid for standard conditions 25°C, 1 atm):

For other reactions we refer to the free software.   [ Demo: online pH-calculator ]

pH of Organic Acids – Sorted by Molecular Formula

Formula Name Alternative name 1 mM 10 mM 100 mM
CH2O2 formic acid methanoic acid 3.47 2.91 2.38
C2H2O3 glyoxilic acid oxoacetic acid 3.27 2.65 2.11
C2H2O4 oxalic acid ethanedioic acid 3.00 2.09 1.31
C2H4O2 acetic acid ethanoic acid 3.91 3.39 2.88
C2H4O3 glocolic acid hydroxyacetic acid 3.50 2.94 2.42
C3H4O2 acrylic acid propenoic acid 3.68 3.14 2.63
C3H4O3 pyruvic acid acetylformic acid 3.11 2.38 1.79
C3H4O4 malonic acid propanedioic acid 3.17 2.50 1.94
C3H6O2 propanoic acid propionic acid 3.96 3.44 2.94
C3H6O3 3-hydroxypropanoic hydracrylic acid 3.79 3.27 2.76
C3H6O3 lactic acid milk acid 3.51 2.96 2.44
C3H6O4 glyceric acid   3.38 2.80 2.27
C4H4O4 fumaric acid allomaleic acid 3.19 2.57 2.03
C4H4O4 maleic acid toxilic acid 3.05 2.21 1.54
C4H4O5 oxaloacetic acid oxalacetic acid 3.05 2.29 1.68
C4H6O2 crotonoic acid 3-butenoic acid 3.84 3.32 2.81
C4H6O3 acetoacetic acid diacetic acid 3.40 2.83 2.30
C4H6O3 2-oxobutanoic acid alpha-ketobutyric acid 3.11 2.38 1.79
C4H6O4 methylmalonic acid   3.23 2.60 2.05
C4H6O4 succinic acid butanedioic acid 3.65 3.12 2.61
C4H6O5 malic acid   3.33 2.74 2.21
C4H6O6 L-tartaric acid racemic acid 3.18 2.55 2.01
C4H6O6 DL-tartaric acid racemic acid 3.19 2.58 2.03
C4H6O6 meso-tartaric acid racemic acid 3.24 2.62 2.08
C4H6O8 dihydroxytartaric acid   3.04 2.20 1.54
C4H8O2 butanoic acid butyric acid 3.94 3.42 2.92
C4H8O2 isobutanoic acid isobutyric acid 3.96 3.44 2.93
C4H8O3 hydroxybutanoic acid   3.43 2.86 2.33
C5H6O4 itaconic acid methylenesuccinic acid 3.50 2.95 2.43
C5H6O4 mesaconic acid dimethylfumaric acid 3.23 2.61 2.06
C5H6O5 oxoglutaric acid ketoglutaric acid 3.09 2.36 1.77
C5H8O4 glutaric acid pentanedioic acid 3.70 3.17 2.66
C5H8O4 methylsuccinic acid   3.62 3.08 2.57
C5H10O2 valeric acid pentanoic acid 3.95 3.43 2.92
C5H10O2 isovaleric acid isopentanoic acid 3.92 3.40 2.89
C5H10O2 pivalic acid dimethylpropanoic acid 4.04 3.52 3.02
C6H6O phenol carbolic acid 6.47 5.99 5.49
C6H6O6 cis-aconitic acid   3.05 2.21 1.55
C6H6O6 trans-aconitic acid   3.14 2.48 1.92
C6H8O6 ascorbic acid vitamin C 3.59 3.04 2.53
C6H8O7 citric acid   3.24 2.62 2.08
C6H8O7 isocitric acid   3.28 2.69 2.16
C6H10O4 adipic acid hexanediodic acid 3.74 3.22 2.71
C6H12O2 caproic acid hexanoic acid 3.95 3.43 2.93
C7H6O2 benzoic acid   3.66 3.12 2.60
C7H6O3 salicylic acid 2-hydroxybenzoic acid 3.21 2.57 2.02
C7H6O4 gentisic acid “2,5-dihydroxybenzoic” 3.21 2.56 2.01
C7H6O4 protocatechuic acid “3,4-dihydroxybenzoic” 3.78 3.25 2.74
C7H6O5 gallic acid “3,4,5-trihydroxybenz.” 3.75 3.22 2.71
C7H12O2 cyclohexanecarboxylic   3.97 3.46 2.95
C7H12O4 pimelic acid heptanedioic acid 3.77 3.25 2.74
C8H6O4 phthalic acid ortho-phthalic acid 3.20 2.55 2.00
C8H6O4 isophthalic acid meta-phthalic acid 3.33 2.76 2.24
C8H6O4 terephthalic acid para-phthalic acid 3.36 2.79 2.26
C8H8O2 phenylacetic acid benzeneacetic acid 3.70 3.17 2.66
C8H8O2 toluic acid ortho-toluic acid 3.53 2.98 2.46
C8H8O2 m-toluic acid meta-toluic acid 3.69 3.15 2.64
C8H8O2 p-toluic acid para-toluic acid 3.73 3.20 2.69
C8H8O3 mandelic acid phenylglycolic acid 3.34 2.75 2.22
C8H8O4 homogentistic acid   3.74 3.21 2.70
C8H14O4 suberic acid octanedioic acid 3.79 3.27 2.76
C8H16O2 octanoic acid caprylic acid 3.97 3.45 2.95
C9H8O2 cinnamic acid trans-cinnamic acid 3.76 3.23 2.72
C9H18O2 nonanoic acid pelargonic acid 4.00 3.49 2.98

pH of Organic Acids – Sorted by increasing pH

Formula Name Alternative name 1 mM 10 mM 100 mM
C2H2O4 oxalic acid ethanedioic acid 3.00 2.09 1.31
C4H4O4 maleic acid toxilic acid 3.05 2.21 1.54
C4H6O8 dihydroxytartaric acid   3.04 2.20 1.54
C6H6O6 cis-aconitic acid   3.05 2.21 1.55
C4H4O5 oxaloacetic acid oxalacetic acid 3.05 2.29 1.68
C5H6O5 oxoglutaric acid ketoglutaric acid 3.09 2.36 1.77
C3H4O3 pyruvic acid acetylformic acid 3.11 2.38 1.79
C4H6O3 2-oxobutanoic acid alpha-ketobutyric acid 3.11 2.38 1.79
C6H6O6 trans-aconitic acid   3.14 2.48 1.92
C3H4O4 malonic acid propanedioic acid 3.17 2.50 1.94
C8H6O4 phthalic acid ortho-phthalic acid 3.20 2.55 2.00
C4H6O6 L-tartaric acid racemic acid 3.18 2.55 2.01
C7H6O4 gentisic acid “2,5-dihydroxybenzoic” 3.21 2.56 2.01
C7H6O3 salicylic acid 2-hydroxybenzoic acid 3.21 2.57 2.02
C4H4O4 fumaric acid allomaleic acid 3.19 2.57 2.03
C4H6O6 DL-tartaric acid racemic acid 3.19 2.58 2.03
C4H6O4 methylmalonic acid   3.23 2.60 2.05
C5H6O4 mesaconic acid dimethylfumaric acid 3.23 2.61 2.06
C4H6O6 meso-tartaric acid racemic acid 3.24 2.62 2.08
C6H8O7 citric acid   3.24 2.62 2.08
C2H2O3 glyoxilic acid oxoacetic acid 3.27 2.65 2.11
C6H8O7 isocitric acid   3.28 2.69 2.16
C4H6O5 malic acid   3.33 2.74 2.21
C8H8O3 mandelic acid phenylglycolic acid 3.34 2.75 2.22
C8H6O4 isophthalic acid meta-phthalic acid 3.33 2.76 2.24
C8H6O4 terephthalic acid para-phthalic acid 3.36 2.79 2.26
C3H6O4 glyceric acid   3.38 2.80 2.27
C4H6O3 acetoacetic acid diacetic acid 3.40 2.83 2.30
C4H8O3 hydroxybutanoic acid   3.43 2.86 2.33
CH2O2 formic acid methanoic acid 3.47 2.91 2.38
C2H4O3 glocolic acid hydroxyacetic acid 3.50 2.94 2.42
C5H6O4 itaconic acid methylenesuccinic acid 3.50 2.95 2.43
C3H6O3 lactic acid milk acid 3.51 2.96 2.44
C8H8O2 toluic acid ortho-toluic acid 3.53 2.98 2.46
C6H8O6 ascorbic acid vitamin C 3.59 3.04 2.53
C5H8O4 methylsuccinic acid   3.62 3.08 2.57
C7H6O2 benzoic acid   3.66 3.12 2.60
C4H6O4 succinic acid butanedioic acid 3.65 3.12 2.61
C3H4O2 acrylic acid propenoic acid 3.68 3.14 2.63
C8H8O2 m-toluic acid meta-toluic acid 3.69 3.15 2.64
C5H8O4 glutaric acid pentanedioic acid 3.70 3.17 2.66
C8H8O2 phenylacetic acid benzeneacetic acid 3.70 3.17 2.66
C8H8O2 p-toluic acid para-toluic acid 3.73 3.20 2.69
C8H8O4 homogentistic acid   3.74 3.21 2.70
C6H10O4 adipic acid hexanediodic acid 3.74 3.22 2.71
C7H6O5 gallic acid “3,4,5-trihydroxybenz.” 3.75 3.22 2.71
C9H8O2 cinnamic acid trans-cinnamic acid 3.76 3.23 2.72
C7H6O4 protocatechuic acid “3,4-dihydroxybenzoic” 3.78 3.25 2.74
C7H12O4 pimelic acid heptanedioic acid 3.77 3.25 2.74
C3H6O3 3-hydroxypropanoic hydracrylic acid 3.79 3.27 2.76
C8H14O4 suberic acid octanedioic acid 3.79 3.27 2.76
C4H6O2 crotonoic acid 3-butenoic acid 3.84 3.32 2.81
C2H4O2 acetic acid ethanoic acid 3.91 3.39 2.88
C5H10O2 isovaleric acid isopentanoic acid 3.92 3.40 2.89
C4H8O2 butanoic acid butyric acid 3.94 3.42 2.92
C5H10O2 valeric acid pentanoic acid 3.95 3.43 2.92
C4H8O2 isobutanoic acid isobutyric acid 3.96 3.44 2.93
C6H12O2 caproic acid hexanoic acid 3.95 3.43 2.93
C3H6O2 propanoic acid propionic acid 3.96 3.44 2.94
C7H12O2 cyclohexanecarboxylic   3.97 3.46 2.95
C8H16O2 octanoic acid caprylic acid 3.97 3.45 2.95
C9H18O2 nonanoic acid pelargonic acid 4.00 3.49 2.98
C5H10O2 pivalic acid dimethylpropanoic acid 4.04 3.52 3.02
C6H6O phenol carbolic acid 6.47 5.99 5.49

pH of Organic Salts – Sorted by Molecular Formula

Formula Name 1 mM 10 mM 100 mM 1000 mM
(NH4)2C6H6O7 diammonium hydrogen citrate 5.48 5.29 5.04 6.16
(NH4)3C6H5O7 triammonium citrate 7.50 7.40 7.32 8.18
Ca(CH3COO)2 calcium acetate 8.00 8.43 8.77 9.13
Ca(HCOO)2 calcium formate 7.51 7.92 8.24 8.47
CaHC6H5O7 calcium hydrogen citrate 4.81 4.44 4.12 3.85
Ca(C3H5O3)2 calcium lactate 7.56 7.97 8.28 8.50
Fe(HCOO)2 iron(II) formate 6.82 6.89 7.03 7.21
K2HC6H5O7 dipotassium hydrogen citrate 5.48 5.27 4.87 3.67
K3C6H5O7 tripotassium citrate 8.59 8.90 9.01 7.47
KCH3COO potassium acetate 7.87 8.33 8.75 9.06
KHCOO potassium formate 7.40 7.83 8.25 8.58
KH2C6H5O7 potassium dihydrogen citrate 4.07 3.87 3.71 3.54
KC3H5O3 potassium lactate 7.45 7.89 8.30 8.62
Mg(CH3COO)2 magnesium acetate 7.95 8.23 8.41 8.78
Mg(HCOO)2 magnesium formate 7.46 7.73 7.90 8.06
MgHC6H5O7 magnesium hydrogen citrate 4.79 4.40 4.08 3.79
Mg(C3H5O3)2 magnesium lactate 7.52 7.78 7.94 8.09
Na2HC6H5O7 disodium hydrogen citrate 5.48 5.28 4.88 3.72
Na3C6H5O7 trisodium citrate 8.59 8.90 9.04 9.26
NaCH3COO sodium acetate 7.87 8.33 8.75 9.04
NaHCOO sodium formate 7.40 7.83 8.25 8.57
NaH2C6H5O7 sodium dihydrogen citrate 4.07 3.87 3.71 3.48
NaHC6H6O6 sodium ascorbate 7.48 7.71 7.64 7.62
NaC3H5O3 sodium lactate 7.48 7.85 8.30 8.61
NH4CH3COO ammonium acetate 7.00 7.00 7.00 6.95
NH4HCOO ammonium formate 6.53 6.50 6.49 6.45
NH4C6H7O7 ammonium dihydrogen citrate 4.07 3.87 3.72 3.71
NH4C6H7O6 ammonium ascorbate 6.66 6.64 6.64 6.59
NH4C3H5O3 ammonium lactate 6.58 6.56 6.55 6.50
[last modified: 2015-11-14]