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Home , Acid, Adipic acid, Anthranilic acid, Arsenic acid, Carboxylic acid, Chloroacetic acid

harxxxxx_App-G.qxd 3/8/10 1:34 PM Page AP11

APPENDIX G Constants

¤␮ 0.1 M 0 ؍ (Ionic strength (␮ † ‡ † Name Structure* pKa Ka pKa 5 CH3CO2H 4.756 1.75 10 4.56 (ethanoic acid)

N H3 3 CHCH3 2.344 (CO2H) 4.53 10 2.33 10 9.868 (NH3) 1.36 10 9.71 CO2H

5 Aminobenzene NH3 4.601 2.51 10 4.64 ()

O SN 4 4-Aminobenzenesulfonic acid 3 H3 3.232 5.86 10 3.01 ()

NH3 3 2-Aminobenzoic acid 2.08 (CO2H) 8.3 10 2.01 5 () 4.96 (NH3) 1.10 10 4.78 CO2H

2-Aminoethanethiol HSCH2CH2NH3 —— 8.21 (SH) (2-mercaptoethylamine) —— 10.73 (NH3)

10 2-Aminoethanol HOCH2CH2NH3 9.498 3.18 10 9.52 ()

O H 5 4.70 (NH3) (20¡) 2.0 10 4.74 2-Aminophenol 9.97 (OH) (20¡) 1.05 10 10 9.87 NH3

10 NH4 9.245 5.69 10 9.26 N H3 N H2 2 1.823 (CO2H) 1.50 10 2.03 CHCH CH CH NHC 9 2 2 2 8.991 (NH3) 1.02 10 9.00 NH —— (NH2) —— (12.1) CO2H 2

O 2.24 5.8 10 3 2.15 acid HO As OH 6.96 1.10 10 7 6.65 ( ) (11.50) 3.2 10 12 (11.18) OH

10 Arsenious acid As(OH)3 9.29 5.1 10 9.14 (hydrogen arsenite)

N O H3

Asparagine CHCH2CNH2 —— —— 2.16 (CO2H) —— —— 8.73 (NH3) CO2H

*Each acid is written in its protonated form. The acidic are indicated in bold type. † Њ pKa values refer to 25 C unless otherwise indicated. Values in parentheses are considered to be less reliable. Data are from A. E. Martell, R. M. Smith, and R. J. Motekaitis, NIST 46 (Gaithersburg, MD: National Institute of Standards and Technology, 2001). ‡ pKb The accurate way to calculate Kb for the conjugate is pKb 13.995 pKa and Kb 10 . ¤ ␮ ␮ See marginal note on page 166 for distinction between pKa at 0 and at 0.1 M. (Continued)

APPENDIX G Acid Dissociation Constants AP11 harxxxxx_App-G.qxd 2/15/10 5:25 PM Page AP12

␮ 0.1 M 0 ؍ (Ionic strength (␮

Name Structure pKa Ka pKa NH 3 2 1.990 ( -CO2H) 1.02 10 1.95 CHCH CO 4 2 2H 3.900 ( -CO2H) 1.26 10 3.71 10.002 (NH ) 9.95 10 11 9.96 3 CO2H

9 —— Aziridine NH2 8.04 9.1 10 (dimethyleneimine)

CO 3 2H 2.86 1.38 10 2.67 CO 5 -1,2,3-tricarboxylic acid 2H 4.30 5.0 10 3.91 (hemimellitic acid) 6.28 5.2 10 7 5.50

CO2H

CO 5 2H 4.202 6.28 10 4.01

CH N 10 Benzylamine 2 H3 9.35 4.5 10 9.40

—— —— (1.3) 5 2,2 -Bipyridine N N 4.34 4.6 10 4.41 HH 9.237 5.79 10 10 8.98 13 B(OH)3 (12.74) (20¡) 1.82 10 —— (hydrogen borate) (13.80) (20¡) 1.58 10 14 ——

3 BrCH2CO2H 2.902 1.25 10 2.71

ON NO H H -2,3-dione dioxime 10.66 2.2 10 11 10.45 (dimethylglyoxime) CH (12.0) 1 10 12 (11.9) CH3 3

5 Butanoic acid CH3CH2CH2CO2H 4.818 1.52 10 4.62

CO 2H cis-Butenedioic acid 1.92 1.20 10 2 1.75 7 () CO 6.27 5.37 10 5.84 2H

CO2H trans-Butenedioic acid 3.02 9.5 10 4 2.84 () 4.48 3.3 10 5 4.09 HO2C

11 Butylamine CH3CH2CH2CH2NH3 10.640 2.29 10 10.66

O * 6.351 4.46 10 7 6.13 11 (hydrogen ) HO C OH 10.329 4.69 10 9.91

3 ClCH2CO2H 2.865 1.36 10 2.69

5 3-Chloropropanoic acid ClCH2CH2CO2H 4.11 7.8 10 3.92

HOCl£O 1.96 1.10 10 2 —— (hydrogen )

*The of “carbonic acid” is considered to be the sum [H2CO3] [CO2(aq)]. See Box 6-4.

AP12 APPENDIX G Acid Dissociation Constants harxxxxx_App-G.qxd 2/15/10 5:25 PM Page AP13

␮ 0.1 M 0 ؍ (Ionic strength (␮

Name Structure pKa Ka pKa O

Chromic acid HO Cr OH (0.2) (20¡) 1.6 (0.6) (20C) 7 6.05 (hydrogen chromate) O 6.51 3.1 10

4 CO2H 3.128 7.44 10 2.90 5 (2-hydroxypropane-1,2,3- 4.761 1.73 10 4.35 O CCH CCH CO 7 tricarboxylic acid) H 2 2 2 2H 6.396 4.02 10 5.70 OH

3 NCCH2CO2H 2.472 3.37 10 ——

11 Cyclohexylamine NH3 10.567 2.71 10 10.62

N 2 H3 (1.7) (CO2H) 2 10 (1.90) 8.36 (SH) 4.4 10 9 8.18 CHCH SH 11 2 10.74 (NH3) 1.82 10 10.30

CO2H

2 Cl2CHCO2H (1.1) 8 10 (0.9)

11 (CH3CH2)2NH2 11.00 1.0 10 11.04

OH 1,2-Dihydroxybenzene 9.45 3.5 10 10 9.26 () —— —— (13.3) OH

OH 1,3-Dihydroxybenzene —— —— 9.30 () —— —— 11.06 OH

OH

4 D-2,3-Dihydroxybutanedioic HO2CCHCHCO2H 3.036 9.20 10 2.82 5 acid (D-) 4.366 4.31 10 3.97 OH

HOCH CHCH SH 2,3-Dimercaptopropanol 2 2 —— —— 8.63 SH —— —— 10.65

11 Dimethylamine (CH3)2NH2 10.774 1.68 10 10.81

NO2 2,4-Dinitrophenol 4.114 7.69 10 5 3.92 O2N OH

Ethane-1,2-dithiol HSCH2CH2SH —— —— 8.85 (30 C) —— —— 10.43 (30C)

11 Ethylamine CH3CH2NH3 10.673 2.12 10 10.69

7 NCH CH N 6.848 1.42 10 7.11 H3 2 2 H3 10 (1,2-diaminoethane) 9.928 1.18 10 9.92

(Continued)

APPENDIX G Acid Dissociation Constants AP13 harxxxxx_App-G.qxd 2/15/10 5:25 PM Page AP14

␮ 0.1 M 0 ؍ (Ionic strength (␮

Name Structure pKa Ka pKa —— (CO2H) —— (0.0) (CO2H) ( 1 M) —— (CO2H) —— (1.5) (CO2H) ( O CCH ) N CH CH N (CH CO ) Ethylenedinitrilotetraacetic H 2 2 2 H 2 2 H 2 2H 2 —— (CO2H) —— 2.00 (CO2H) —— (CO2H) 2.69 (CO2H) acid (EDTA) —— 6.273 (NH) 5.3 10 7 6.13 (NH) 10.948 (NH) 1.13 10 11 10.37 (NH)

4 HCO2H 3.744 1.80 10 3.57 (methanoic acid) NH 3 3 2.160 ( -CO2H) 6.92 10 2.16 CHCH CH CO 5 2 2 2H 4.30 ( -CO2H) 5.0 10 4.15 9.96 (NH ) 1.10 10 10 9.58 3 CO2H

N O H3

Glutamine CHCH2CH2CNH2 —— —— 2.19 (CO2H) —— —— 9.00 (NH3) CO2H

NH3 CH 3 2 2.350 (CO2H) 4.47 10 2.33 10 (aminoacetic acid) 9.778 (NH3) 1.67 10 9.57 CO2H

NH2 Guanidine —— —— (13.5) (1 M) H2N CNH2

1,6-Hexanedioic acid 4.424 3.77 10 5 4.26 HO2CCH2CH2CH2CH2CO2H () 5.420 3.80 10 6 5.04 O O Hexane-2,4-dione 9.38 4.2 10 10 9.11 (20C) CH 3CCH2CCH2CH3

NH 3 NH 2 (1.6) (CO2H) 3 10 (1.7) CHCH 6 2 5.97 (NH) 1.07 10 6.05 N 10 H 9.28 (NH3) 5.2 10 9.10 CO2H

1 H3N NH3 0.99 1.0 10 (0.21) (0.5 M) 7.98 1.05 10 8 8.07

HNNN 4.65 2.2 10 5 4.45 (hydrogen azide)

Hydrogen HOCΩN 3.48 3.3 10 4 ——

HCΩN 9.21 6.2 10 10 9.04

Hydrogen fluoride HF 3.17 6.8 10 4 2.94

HOOH 11.65 2.2 10 12 —— 8 Hydrogen sulfide H2S 7.02 9.5 10 6.82 14.0* 1.0 10 14* ——

Hydrogen HSCΩN(1.1) (20¡C) 1.3 101 —— 4 Hydroxyacetic acid HOCH2CO2H 3.832 1.48 10 3.62 ()

*D. J. Phillips and S. L. Phillips. “High Dissociation Constants of HS and the Standard Thermodynamic Values for S2 ,” J. Chem. Eng. Data 2000, 45, 981.

AP14 APPENDIX G Acid Dissociation Constants harxxxxx_App-G.qxd 2/15/10 5:25 PM Page AP15

␮ 0.1 M 0 ؍ (Ionic strength (␮

Name Structure pKa Ka pKa 10 Hydroxybenzene OH 9.997 1.01 10 9.78 ()

CO 2H 3 2-Hydroxybenzoic acid 2.972 (CO2H) 1.07 10 2.80 14 () OH (13.7) (OH) 2 10 (13.4)

OH 4 L-Hydroxybutanedioic acid 3.459 3.48 10 3.24 () 5.097 8.00 10 6 4.68 HO2CCH2CHCO2H

6 Hydroxylamine HONH3 5.96 (NH) 1.10 10 5.96 (13.74) (OH) 1.8 10 14 ——

8-Hydroxyquinoline 4.94 (NH) 1.15 10 5 4.97 N 10 (oxine) H 9.82 (OH) 1.51 10 9.65 HO

HOBr 8.63 2.3 10 9 —— (hydrogen )

HOCl 7.53 3.0 10 8 —— (hydrogen )

HOI 10.64 2.3 10 11 —— (hydrogen hypoiodite)

O (1.3) 5 10 2 (1.1) H (hydrogen hypophosphite) 2POH

NH 6.993 1.02 10 7 7.00 (1,3-diazole) (14.5) 15 —— N 3 10 H

2 (1.85) (CO2H) 1.41 10 (1.77) N(CH CO ) 3 Iminodiacetic acid H2 2 2H 2 2.84 (CO2H) 1.45 10 2.62 10 9.79 (NH2) 1.62 10 9.34 O Iodic acid 0.77 0.17 —— (hydrogen iodate) HOI O

4 ICH2CO2H 3.175 6.68 10 2.98

NH3 CHCH(CH )CH CH 3 3 2 3 2.318 (CO2H) 4.81 10 2.26 10 9.758 (NH3) 1.75 10 9.60 CO2H

NH3 CHCH CH(CH ) 3 2 3 2 2.328 (CO2H) 4.70 10 2.32 10 9.744 (NH3) 1.80 10 9.58 CO2H

NH 3 2 (1.77) (CO2H) 1.7 10 2.15 CHCH CH CH CH N 10 2 2 2 2 H3 9.07 ( -NH3) 8.5 10 9.15 11 10.82 ( -NH3) 1.51 10 10.66 CO2H

(Continued)

APPENDIX G Acid Dissociation Constants AP15 harxxxxx_App-G.qxd 2/15/10 5:25 PM Page AP16

␮ 0.1 M 0 ؍ (Ionic strength (␮

Name Structure pKa Ka pKa 3 HO2CCH2CO2H 2.847 1.42 10 2.65 6 (propanedioic acid) 5.696 2.01 10 5.27

4 Mercaptoacetic acid HSCH2CO2H 3.64 (CO2H) 2.3 10 3.48 11 () 10.61 (SH) 2.5 10 10.11

10 2-Mercaptoethanol HSCH2CH2OH 9.72 1.9 10 9.40

NH3 CHCH CH SCH 2 2 3 —— —— 2.18 (CO2H) —— —— 9.08 (NH3) CO2H

OCH3 2-Methoxyaniline 4.526 2.98 10 5 —— (o-anisidine) NH3

6 5.33 4-Methoxyaniline CH O NH 5.357 4.40 10 (p-anisidine) 3 3

11 10.65 CH3NH3 10.632 2.33 10

CH 3 2-Methylaniline 4.447 3.57 10 5 —— (o-toluidine) NH3

4-Methylaniline 5.080 6 5.09 CH N 8.32 10 (p-toluidine) 3 H3

CH 3 2-Methylphenol 10.31 4.9 10 11 10.09 (o-cresol) OH

4-Methylphenol 10.269 5.5 10 11 10.04 CH OH (p-cresol) 3

9 8.492 3.22 10 —— O NH (perhydro-1,4-oxazine) 2

CO2H 1-Naphthoic acid 3.67 2.1 10 4 ——

CO 2H 2-Naphthoic acid 4.16 6.9 10 5 ——

OH 1-Naphthol 9.416 3.84 10 10 9.14

OH 2-Naphthol 9.573 2.67 10 10 9.31

—— (CO2H) —— (1.0) N(CH CO ) 2.0 (CO2H) (25¡) 0.010 1.81 Nitrilotriacetic acid H 2 2H 3 3 2.940 (CO2H) (20¡) 1.15 10 2.52 10.334 (NH) (20¡) 4.63 10 11 9.46

AP16 APPENDIX G Acid Dissociation Constants harxxxxx_App-G.qxd 2/15/10 10:24 PM Page AP17

␮ ϭ 0.1 M 0 ؍ (Ionic strength (␮

Name Structure pKa Ka pKa

NO2 Ϫ 2-Nitrobenzoic acid 2.185 6.53 ϫ 10 3 —— CO 2H

NO2

Ϫ 3-Nitrobenzoic acid 3.449 3.56 ϫ 10 4 3.28

CO2H

O N CO Ϫ4 4-Nitrobenzoic acid 2 2H 3.442 3.61 ϫ 10 3.28

ϫ Ϫ9 CH3CH2NO2 8.57 2.7 10 ——

NO2 Ϫ 2-Nitrophenol 7.230 5.89 ϫ 10 8 7.04 OH

NO2 Ϫ 3-Nitrophenol 8.37 4.3 ϫ 10 9 8.16 OH

O N O Ϫ8 4-Nitrophenol 2 H 7.149 7.10 ϫ 10 6.96

NO N-Nitrosophenylhydroxylamine N —— —— 4.16 (cupferron) OH

Ϫ HON£O 3.15 7.1 ϫ 10 4 ——

Ϫ HO2CCO2H 1.250 5.62 ϫ 10 2 (1.2) Ϫ (ethanedioic acid) 4.266 5.42 ϫ 10 5 3.80

O Ϫ Oxoacetic acid 3.46 3.5 ϫ 10 4 3.05 HCCO () 2H

O Ϫ Oxobutanedioic acid 2.56 2.8 ϫ 10 3 2.26 O CCH CCO ϫ Ϫ5 () H 2 2 2H 4.37 4.3 10 3.90

O 2-Oxopentanedioic —— —— (1.9) (␮ϭ0.5 M) (␣-ketoglutaric acid) —— —— 4.44 (␮ϭ0.5 M) HO2CCH2CH2CCO2H

O Ϫ 2-Oxopropanoic acid 2.48 3.3 ϫ 10 3 2.26 CH () 3CCO2H

Ϫ 1,5-Pentanedioic acid HO2CCH2CH2CH2CO2H 4.345 4.52 ϫ 10 5 4.19 Ϫ () 5.422 3.78 ϫ 10 6 5.06 ϫ Ϫ5 Њ Pentanoic acid CH3CH2CH2CH2CO2H 4.843 1.44 10 4.63 (18 C) ()

1,10- —— —— (1.8) Ϫ5 N N 4.91 1.23 ϫ 10 4.92 ϩϩH H

CH CO Ϫ5 2 2H 4.310 4.90 ϫ 10 4.11

(Continued)

APPENDIX G Acid Dissociation Constants AP17 harxxxxx_App-G.qxd 2/15/10 5:25 PM Page AP18

␮ 0.1 M 0 ؍ (Ionic strength (␮

Name Structure pKa Ka pKa NH 3 3 CHCH 2.20 (CO2H) 6.3 10 2.18 2 10 9.31 (NH3) 4.9 10 9.09 CO 2H

O 2.148 7.11 10 3 1.92 * HO P OH 7.198 6.34 10 8 6.71 (hydrogen ) 12.375 4.22 10 13 11.52 OH

O

HP OH (1.5) 3 10 2 —— (hydrogen phosphite) 6.78 1.66 10 7 —— OH

CO H 2 2.950 1.12 10 3 2.76 (benzene-1,2-) 5.408 3.90 10 6 4.92 CO2H

5.333 4.65 10 6 5.64 H N NH (perhydro-1,4-diazine) 2 2 9.731 1.86 10 10 9.74

12 NH2 11.125 7.50 10 11.08

CO 2H 2 1.952 (CO2H) 1.12 10 1.89 N 10.640 (NH ) 2.29 10 11 10.46 H2 2

5 Propanoic acid CH3CH2CO2H 4.874 1.34 10 4.69

£ 5 Propenoic acid H2C CHCO2H 4.258 5.52 10 —— ()

11 CH3CH2CH2NH3 10.566 2.72 10 10.64

6 5.20 6.3 10 5.24 NH (azine)

N H 2 Pyridine-2- (1.01) (CO2H) 9.8 10 (0.95) (picolinic acid) 5.39 (NH) 4.1 10 6 5.21 CO2H

HO2C 3 Pyridine-3-carboxylic acid 2.03 (CO2H) 9.3 10 2.08 5 (nicotinic acid) NH 4.82 (NH) 1.51 10 4.69

O O CH —— —— (1.4) (POH) POCH O Pyridoxal-5-phosphate HO 2 H —— —— 3.51 (OH) —— —— 6.04 (POH) HO N CH —— —— 8.25 (NH) H 3

Pyrophosphoric acid O O (0.9) 0.13 (0.8) (hydrogen diphosphate) 2.28 5.2 10 3 (1.9) ( O) POP(O ) H 2 H 2 6.70 2.0 10 7 5.94 9.40 4.0 10 10 8.25

*pK3 from A. G. Miller and J. W. Macklin, Anal. Chem. 1983, 55, 684.

AP18 APPENDIX G Acid Dissociation Constants harxxxxx_App-G.qxd 2/15/10 5:25 PM Page AP19

␮ 0.1 M 0 ؍ (Ionic strength (␮

Name Structure pKa Ka pKa

12 NH2 11.305 4.95 10 11.3

NH 3 CHCH OH 3 2 2.187 (CO2H) 6.50 10 2.16 10 9.209 (NH3) 6.18 10 9.05 CO2H

5 3.99 HO2CCH2CH2CO2H 4.207 6.21 10 (butanedioic acid) 5.636 2.31 10 6 5.24 O

O S O 2 H H 1.987 (pK2) 1.03 10 1.54 (hydrogen ) O

O 1.857 1.39 10 2 1.66 8 (hydrogen sulfite) HOSOH 7.172 6.73 10 6.85

O

Thiosulfuric acid HOSSH (0.6) 0.3 —— (hydrogen ) (1.6) 0.03 (1.3) O

NH 3 CHCHOHCH 3 3 2.088 (CO2H) 8.17 10 2.20 10 9.100 (NH3) 7.94 10 8.94 CO2H

Cl3CCO2H ( 0.5) 3 —— 8 (HOCH2CH2)3NH 7.762 1.73 10 7.85 11 (CH3CH2)3NH 10.72 1.9 10 10.76

OH 1,2,3-Trihydroxybenzene OH —— —— 8.96 () —— —— 11.00 —— —— (14.0) (20C) OH

10 (CH3)3NH 9.799 1.59 10 9.82

9 Tris(hydroxymethyl)amino- (HOCH2)3CNH3 8.072 8.47 10 8.10 methane (tris or tham)

NH 3 CHCH 2 —— —— 2.37 (CO2H) CO N —— —— 9.33 (NH3) 2H H

NH3 —— —— 2.41 (CO2H) CHCH2 OH —— —— 8.67 (NH3) —— —— 11.01 (OH) CO2H

NH 3 CHCH(CH ) 3 3 2 2.286 (CO2H) 5.18 10 2.27 10 9.719 (NH3) 1.91 10 9.52 CO2H

14 * H2O 13.997 1.01 10 ——

*The constant given for water is Kw.

APPENDIX G Acid Dissociation Constants AP19