Tablas i Ones

ELECTROCHEMICAL SERIES

Petr Vanysek

There are three tables for this electrochemical series. Each table lists standard reduction potentials, E° values, at 298.15 K (25°C), and at a pressure

of 101.325 kPa (1 atm). Table 1 is an alphabetical listing of the elements, according to the symbol of the elements. Thus, data for silver (Ag) precedesthose for aluminum (Al). Table 2 lists only those reduction reactions which have E° values positive in respect to the standard hydrogen electrode. InTable 2, the reactions are listed in the order of increasing positive potential, and they range from 0.0000 V to + 3.4 V. Table 3 lists only those reduction

potentials which have E° negative with respect to the standard hydrogen electrode. In Table 3, the reactions are listed in the order of decreasing potentialand range from 0.0000 V to –4.10 V. The reliability of the potentials is not the same for all the data. Typically, the values with fewer significant figureshave lower reliability. The values of reduction potentials, in particular those of less common reactions, are not definite; they are subject to occasional

revisions.

Abbreviations: ac = acetate; bipy = 2,2′-dipyridine, or bipyridine; en = ethylenediamine; phen = 1,10-phenanthroline.

REFERENCES

1. G. Milazzo, S. Caroli, and V. K. Sharma, Tables of Standard Electrode Potentials, Wiley, Chichester, 1978.2. A. J. Bard, R. Parsons, and J. Jordan, Standard Potentials in Aqueous Solutions, Marcel Dekker, New York, 1985.

3. S. G. Bratsch, J. Phys. Chem. Ref. Data, 18, 1—21, 1989.

TABLE 1Alphabetical Listing

Reaction E°/V

Ac3+ + 3 e 1 Ac –2.20Ag+ + e 1 Ag 0.7996

Ag2+ + e 1 Ag+ 1.980Ag(ac) + e 1 Ag + (ac)– 0.643AgBr + e 1 Ag + Br– 0.07133

AgBrO3 + e 1 Ag + BrO3– 0.546

Ag2C2O4 + 2 e 1 2 Ag + C2O42– 0.4647

AgCl + e 1 Ag + Cl– 0.22233

AgCN + e 1 Ag + CN– –0.017Ag2CO3 + 2 e 1 2 Ag + CO3

2– 0.47Ag2CrO4 + 2 e 1 2 Ag + CrO4

2– 0.4470

AgF + e 1 Ag + F– 0.779Ag4[Fe(CN)6] + 4 e 1 4 Ag + [Fe(CN)6]

4– 0.1478AgI + e 1 Ag + I– –0.15224

AgIO3 + e 1 Ag + IO3– 0.354

Ag2MoO4 + 2 e 1 2 Ag + MoO42– 0.4573

AgNO2 + e 1 Ag + 2 NO2– 0.564

Ag2O + H2O + 2 e 1 2 Ag + 2 OH– 0.342Ag2O3 + H2O + 2 e 1 2 AgO + 2 OH– 0.739Ag3+ + 2 e 1 Ag+ 1.9

Ag3+ + e 1 Ag2+ 1.8Ag2O2 + 4 H+ + e 1 2 Ag + 2 H2O 1.8022 AgO + H2O + 2 e 1 Ag2O + 2 OH– 0.607

AgOCN + e 1 Ag + OCN– 0.41Ag2S + 2 e 1 2 Ag + S2– –0.691Ag2S + 2 H+ + 2 e 1 2 Ag + H2S –0.0366

AgSCN + e 1 Ag + SCN– 0.08951Ag2SeO3 + 2 e 1 2 Ag + SeO4

2– 0.3629Ag2SO4 + 2 e 1 2 Ag + SO4

2– 0.654

Ag2WO4 + 2 e 1 2 Ag + WO42– 0.4660

Al3+ + 3 e 1 Al –1.662Al(OH)3 + 3 e 1 Al + 3 OH– –2.31

Al(OH)4– + 3 e 1 Al + 4 OH– –2.328

H2AlO3– + H2O + 3 e 1 Al + 4 OH– –2.33

AlF63– + 3 e 1 Al + 6 F– –2.069

Am4+ + e 1 Am3+ 2.60

Am2+ + 2 e 1 Am –1.9Am3+ + 3 e 1 Am –2.048Am3+ + e 1 Am2+ –2.3

As + 3 H+ + 3 e 1 AsH3 –0.608As2O3 + 6 H+ + 6 e 1 2 As + 3 H2O 0.234HAsO2 + 3 H+ + 3 e 1 As + 2 H2O 0.248

AsO2– + 2 H2O + 3 e 1 As + 4 OH– –0.68

H3AsO4 + 2 H+ + 2 e–1 HAsO2 + 2 H2O 0.560

AsO43– + 2 H2O + 2 e 1 AsO2

– + 4 OH– –0.71

At2 + 2 e 1 2 At– 0.3Au+ + e 1 Au 1.692Au3+ + 2 e 1 Au+ 1.401

Au3+ + 3 e 1 Au 1.498Au2+ + e –1 Au+ 1.8AuOH2+ + H+ + 2 e 1 Au+ + H2O 1.32

AuBr2– + e 1 Au + 2 Br– 0.959

AuBr4– + 3 e 1 Au + 4 Br– 0.854

AuCl4– + 3 e 1 Au + 4 Cl– 1.002

Au(OH)3 + 3 H+ + 3 e 1 Au + 3 H2O 1.45H2BO3

– + 5 H2O + 8 e 1 BH4– + 8 OH– –1.24

H2BO3– + H2O + 3 e 1 B + 4 OH– –1.79

H3BO3 + 3 H+ + 3 e 1 B + 3 H2O –0.8698B(OH)3 + 7 H+ + 8 e 1 BH4

– + 3 H2O –0.481Ba2+ + 2 e 1 Ba –2.912

Ba2+ + 2 e 1 Ba(Hg) –1.570Ba(OH)2 + 2 e 1 Ba + 2 OH– –2.99Be2+ + 2 e 1 Be –1.847

Be2O32– + 3 H2O + 4 e 1 2 Be + 6 OH– –2.63

Reaction E°/V

© 2000 by CRC PRESS LLC

ELECTROCHEMICAL SERIES (continued)

TABLE 1Alphabetical Listing (continued)

p–benzoquinone + 2 H+ + 2 e 1 hydroquinone 0.6992

Bi+ + e 1 Bi 0.5Bi3+ + 3 e 1 Bi 0.308Bi3+ + 2 e 1 Bi+ 0.2

Bi + 3 H+ + 3 e 1 BiH3 –0.8BiCl4

– + 3 e 1 Bi + 4 Cl– 0.16Bi2O3 + 3 H2O + 6 e 1 2 Bi + 6 OH– –0.46

Bi2O4 + 4 H+ + 2 e 1 2 BiO+ + 2 H2O 1.593BiO+ + 2 H+ + 3 e 1 Bi + H2O 0.320BiOCl + 2 H+ + 3 e 1 Bi + Cl– + H2O 0.1583

Bk4+ + e 1 Bk3+ 1.67Bk2+ + 2 e 1 Bk –1.6Bk3+ + e 1 Bk2+ –2.8

Br2(aq) + 2 e 1 2 Br– 1.0873Br2(l) + 2 e 1 2 Br– 1.066HBrO + H+ + 2 e 1 Br– + H2O 1.331

HBrO + H+ + e 1 1/2 Br2(aq) + H2O 1.574HBrO + H+ + e 1 1/2 Br2(l) + H2O 1.596BrO– + H2O + 2 e 1 Br– + 2 OH– 0.761

BrO3– + 6 H+ + 5 e 1 1/2 Br2 + 3 H2O 1.482

BrO3– + 6 H+ + 6 e 1 Br– + 3 H2O 1.423

BrO3– + 3 H2O + 6 e 1 Br– + 6 OH– 0.61

(CN)2 + 2 H+ + 2 e 1 2 HCN 0.3732 HCNO + 2 H+ + 2 e 1 (CN)2 + 2 H2O 0.330(CNS)2 + 2 e 1 2 CNS– 0.77

CO2 + 2 H+ + 2 e 1 HCOOH –0.199Ca+ + e 1 Ca –3.80Ca2+ + 2 e 1 Ca –2.868

Ca(OH)2 + 2 e 1 Ca + 2 OH– –3.02Calomel electrode, 1 molal KCl 0.2800Calomel electrode, 1 molar KCl (NCE) 0.2801

Calomel electrode, 0.1 molar KCl 0.3337Calomel electrode, saturated KCl (SCE) 0.2412Calomel electrode, saturated NaCl (SSCE) 0.2360

Cd2+ + 2 e 1 Cd –0.4030Cd2+ + 2 e 1 Cd(Hg) –0.3521Cd(OH)2 + 2 e 1 Cd(Hg) + 2 OH– –0.809

CdSO4 + 2 e 1 Cd + SO42– –0.246

Cd(OH)42– + 2 e 1 Cd + 4 OH– –0.658

CdO + H2O + 2 e 1 Cd + 2 OH– –0.783

Ce3+ + 3 e 1 Ce –2.336Ce3+ + 3 e 1 Ce(Hg) –1.4373Ce4+ + e 1 Ce3+ 1.72

CeOH3+ + H+ + e 1 Ce3+ + H2O 1.715Cf4+ + e 1 Cf3+ 3.3Cf3+ + e 1 Cf2+ –1.6

Cf3+ + 3 e 1 Cf –1.94Cf2+ + 2 e 1 Cf –2.12Cl2(g) + 2 e 1 2 Cl– 1.35827

HClO + H + + e 1 1/2 Cl2 + H2O 1.611HClO + H+ + 2 e 1 Cl– + H2O 1.482ClO– + H2O + 2 e 1 Cl– + 2 OH– 0.81

ClO2 + H+ + e 1 HClO2 1.277HClO2 + 2 H+ + 2 e 1 HClO + H2O 1.645HClO2 + 3 H+ + 3 e 1 1/2 Cl2 + 2 H2O 1.628

HClO2 + 3 H+ + 4 e 1 Cl– + 2 H2O 1.570

ClO2– + H2O + 2 e 1 ClO– + 2 OH– 0.66

ClO2– + 2 H2O + 4 e 1 Cl– + 4 OH– 0.76

ClO2(aq) + e 1 ClO2– 0.954

ClO3– + 2 H+ + e 1 ClO2 + H2O 1.152

ClO3– + 3 H+ + 2 e 1 HClO2 + H2O 1.214

ClO3– + 6 H+ + 5 e 1 1/2 Cl2 + 3 H2O 1.47

ClO3– + 6 H+ + 6 e 1 Cl– + 3 H2O 1.451

ClO3– + H2O + 2 e 1 ClO2

– + 2 OH– 0.33ClO3

– + 3 H2O + 6 e 1 Cl– + 6 OH– 0.62

ClO4– + 2 H+ + 2 e 1 ClO3

– H2O 1.189ClO4

– + 8 H+ + 7 e 1 1/2 Cl2 + 4 H2O 1.39ClO4

– + 8 H+ + 8 e 1 Cl– + 4 H2O 1.389

ClO4– + H2O + 2 e 1 ClO3

– + 2 OH– 0.36Cm4+ + e 1 Cm3+ 3.0Cm3+ + 3 e 1 Cm –2.04

Co2+ + 2 e 1 Co –0.28Co3+ + e 1 Co2+ 1.92[Co(NH3)6]3+ + e 1 [Co(NH3)6]2+ 0.108

Co(OH)2 + 2 e 1 Co + 2 OH– –0.73Co(OH)3 + e 1 Co(OH)2 + OH– 0.17Cr2+ + 2 e 1 Cr –0.913

Cr3+ + e 1 Cr2+ –0.407Cr3+ + 3 e 1 Cr –0.744Cr2O7

2– + 14 H+ + 6 e 1 2 Cr3+ + 7 H2O 1.232

CrO2– + 2 H2O + 3 e 1 Cr + 4 OH– –1.2

HCrO4– + 7 H+ + 3 e 1 Cr3+ + 4 H2O 1.350

CrO2 + 4 H+ + e 1 Cr3+ + 2H2O 1.48

Cr(V) + e 1 Cr(IV) 1.34CrO4

2– + 4 H2O + 3 e 1 Cr(OH)3 + 5 OH– –0.13Cr(OH)3 + 3 e 1 Cr + 3 OH– –1.48

Cs+ + e 1 Cs –3.026Cu+ + e 1 Cu 0.521Cu2+ + e 1 Cu+ 0.153

Cu2+ + 2 e 1 Cu 0.3419Cu2+ + 2 e 1 Cu(Hg) 0.345Cu3+ + e 1 Cu2+ 2.4

Cu2O3 + 6 H+ + 2e 1 2Cu2+ + 3 H2O 2.0Cu2+ + 2 CN– + e 1 [Cu(CN)2]– 1.103CuI2

– + e 1 Cu + 2 I– 0.00

Cu2O + H2O + 2 e 1 2 Cu + 2 OH– –0.360Cu(OH)2 + 2 e 1 Cu + 2 OH– –0.2222 Cu(OH)2 + 2 e 1 Cu2O + 2 OH– + H2O –0.080

2 D+ + 2 e 1 D2 –0.013Dy2+ + 2 e 1 Dy –2.2Dy3+ + 3 e 1 Dy –2.295

Dy3+ + e 1 Dy2+ –2.6Er2+ + 2 e 1 Er –2.0Er3+ + 3 e 1 Er –2.331

Er3+ + e 1 Er2+ –3.0Es3+ + e 1 Es2+ –1.3Es3+ + 3 e 1 Es –1.91

Es2+ + 2 e 1 Es –2.23Eu2+ + 2 e 1 Eu –2.812Eu3+ + 3 e 1 Eu –1.991

Reaction E°/VReaction E°/V




Eu3+ + e 1 Eu2+ –0.36

F2 + 2 H+ + 2 e 1 2 HF 3.053F2 + 2 e 1 2 F– 2.866F2O + 2 H+ + 4 e 1 H2O + 2 F– 2.153

Fe2+ + 2 e 1 Fe –0.447Fe3+ + 3 e 1 Fe –0.037Fe3+ + e 1 Fe2+ 0.771

2 HFeO4– + 8 H+ + 6 e 1 Fe2O3 + 5 H2O 2.09

HFeO4– + 4 H+ + 3 e 1 FeOOH + 2 H2O 2.08

HFeO4– + 7 H+ + 3 e 1 Fe3+ + 4 H2O 2.07

Fe2O3 + 4 H+ + 2 e 1 2 FeOH+ + H2O 0.16[Fe(CN)6]

3– + e 1 [Fe(CN)6]4– 0.358FeO4

2– + 8 H+ + 3 e 1 Fe3+ + 4 H2O 2.20

[Fe(bipy)2]3+ + e 1 Fe(bipy)2]

2+ 0.78[Fe(bipy)3]

3+ + e 1 Fe(bipy)3]2+ 1.03

Fe(OH)3 + e 1 Fe(OH)2 + OH– –0.56

[Fe(phen)3]3+ + e 1 [Fe(phen)3]

2+ 1.147[Fe(phen)3]

3+ + e 1 [Fe(phen)3]2+ (1 molar H2SO4) 1.06

[Ferricinium]+ + e 1 ferrocene 0.400

Fm3++ e 1 Fm2+ –1.1Fm3+ + 3 e 1 Fm –1.89Fm2+ + 2 e 1 Fm –2.30

Fr+ + e 1 Fr –2.9Ga3+ + 3 e 1 Ga –0.549Ga+ + e 1 Ga –0.2

GaOH2+ + H+ + 3 e 1 Ga + H2O –0.498H2GaO–

3 + H2O + 3 e 1 Ga + 4 OH– –1.219Gd3+ + 3 e 1 Gd –2.279

Ge2+ + 2 e 1 Ge 0.24Ge4+ + 4 e 1 Ge 0.124Ge4+ + 2 e 1 Ge2+ 0.00

GeO2 + 2 H+ + 2 e 1 GeO + H2O –0.118H2GeO3 + 4 H+ + 4 e 1 Ge + 3 H2O –0.1822 H+ + 2 e 1 H2 0.00000

H2 + 2 e 1 2 H– –2.23HO2 + H+ + e 1 H2O2 1.4952 H2O + 2 e 1 H2 + 2 OH– –0.8277

H2O2 + 2 H+ + 2 e 1 2 H2O 1.776Hf4+ + 4 e 1 Hf –1.55HfO2+ + 2 H+ + 4 e 1 Hf + H2O –1.724

HfO2 + 4 H+ + 4 e 1 Hf + 2 H2O –1.505HfO(OH)2 + H2O + 4 e 1 Hf + 4 OH– –2.50Hg2+ + 2 e 1 Hg 0.851

2 Hg2+ + 2 e 1 Hg22+ 0.920

Hg22+ + 2 e 1 2 Hg 0.7973

Hg2(ac)2 + 2 e 1 2 Hg + 2(ac)– 0.51163

Hg2Br2 + 2 e 1 2 Hg + 2 Br– 0.13923Hg2Cl2 + 2 e 1 2 Hg + 2 Cl– 0.26808Hg2HPO4 + 2 e 1 2 Hg + HPO4

2– 0.6359

Hg2I2 + 2 e 1 2 Hg + 2 I– –0.0405Hg2O + H2O + 2 e 1 2 Hg + 2 OH– 0.123HgO + H2O + 2 e 1 Hg + 2 OH– 0.0977

Hg(OH)2 + 2 H+ + 2 e 1 Hg + 2 H2O 1.034Hg2SO4 + 2 e 1 2 Hg + SO4

2– 0.6125Ho2+ + 2 e 1 Ho –2.1

Ho3+ + 3 e 1 Ho –2.33

Ho3+ + e 1 Ho2+ –2.8I2 + 2 e 1 2 I– 0.5355I3

– + 2 e 1 3 I– 0.536

H3IO62– + 2 e 1 IO–

3 + 3 OH– 0.7H5IO6 + H+ + 2 e 1 IO3

– + 3 H2O 1.6012 HIO + 2 H+ + 2 e 1 I2 + 2 H2O 1.439

HIO + H+ + 2 e 1 I– + H2O 0.987IO– + H2O + 2 e 1 I– + 2 OH– 0.4852 IO3

– + 12 H+ + 10 e 1 I2 + 6 H2O 1.195

IO3– + 6 H+ + 6 e 1 I– + 3 H2O 1.085

IO3– + 2 H2O + 4 e 1 IO– + 4 OH– 0.15

IO3– + 3 H2O + 6 e 1 IO– + 6 OH– 0.26

In+ + e 1 In –0.14In2+ + e 1 In+ –0.40In3+ + e 1 In2+ –0.49

In3+ + 2 e 1 In+ –0.443In3+ + 3 e 1 In –0.3382In(OH)3 + 3 e 1 In + 3 OH– –0.99

In(OH)4– + 3 e 1 In + 4 OH– –1.007

In2O3 + 3 H2O + 6 e 1 2 In + 6 OH– –1.034Ir3+ + 3 e 1 Ir 1.156

[IrCl6]2– + e 1 [IrCl6]

3– 0.8665[IrCl6]

3– + 3 e 1 Ir + 6 Cl– 0.77Ir2O3 + 3 H2O + 6 e 1 2 Ir + 6 OH– 0.098

K+ + e 1 K –2.931La3+ + 3 e 1 La –2.379La(OH)3 + 3 e 1 La + 3 OH– –2.90

Li+ + e 1 Li –3.0401Lr3+ + 3 e 1 Lr –1.96Lu3+ + 3 e 1 Lu –2.28

Md3+ + e 1 Md2+ –0.1Md3+ + 3 e 1 Md –1.65Md2+ + 2 e 1 Md –2.40

Mg+ + e 1 Mg –2.70Mg2+ + 2 e 1 Mg –2.372Mg(OH)2 + 2 e 1 Mg + 2 OH– –2.690

Mn2+ + 2 e 1 Mn –1.185Mn3+ + 3e 1 Mn2+ 1.5415MnO2 + 4 H+ + 2 e 1 Mn2+ + 2 H2O 1.224

MnO4– + e 1 MnO4

2– 0.558MnO4

– + 4 H+ + 3 e 1 MnO2 + 2 H2O 1.679MnO4

– + 8 H+ + 5 e 1 Mn2+ + 4 H2O 1.507

MnO4– + 2 H2O + 3 e 1 MnO2 + 4 OH– 0.595

MnO42– + 2 H2O + 2 e 1 MnO2 + 4 OH– 0.60

Mn(OH)2 + 2 e 1 Mn + 2 OH– –1.56

Mn(OH)3 + e 1 Mn(OH)2 + OH– 0.15Mn2O3 + 6 H+ + e 1 2 Mn2+ + 3 H2O 1.485Mo3+ + 3 e 1 Mo –0.200

MoO2 + 4 H+ + 4 e 1 Mo + 4 H2O –0.152H3Mo7O24

3– + 45 H+ + 42 e 1 7 Mo + 24 H2O 0.082MoO3 + 6 H+ + 6 e 1 Mo + 3 H2O 0.075

N2 + 2 H2O + 6 H+ + 6 e 1 2 NH4OH 0.0923 N2 + 2 H+ + 2 e 1 2 HN3 –3.09N5

+ + 3 H+ + 2 e 1 2 NH4+ 1.275





N2O + 2 H+ + 2 e 1 N2 + H2O 1.766

H2N2O2 + 2 H+ + 2 e 1 N2 + 2 H2O 2.65N2O4 + 2 e 1 2 NO2

– 0.867N2O4 + 2 H+ + 2 e 1 2 NHO2 1.065

N2O4 + 4 H+ + 4 e 1 2 NO + 2 H2O 1.0352 NH3OH+ + H+ + 2 e 1 N2H5

+ + 2 H2O 1.422 NO + 2 H+ + 2 e 1 N2O + H2O 1.591

2 NO + H2O + 2 e 1 N2O + 2 OH– 0.76HNO2 + H+ + e 1 NO + H2O 0.9832 HNO2 + 4 H+ + 4 e 1 H2N2O2 + 2 H2O 0.86

2 HNO2 + 4 H+ + 4 e 1 N2O + 3 H2O 1.297NO2

– + H2O + e 1 NO + 2 OH– –0.462 NO2

– + 2 H2O + 4 e 1 N2O22– + 4 OH– –0.18

2 NO2– + 3 H2O + 4 e 1 N2O + 6 OH– 0.15

NO3– + 3 H+ + 2 e 1 HNO2 + H2O 0.934

NO3– + 4 H+ + 3 e 1 NO + 2 H2O 0.957

2 NO3– + 4 H+ + 2 e 1 N2O4 + 2 H2O 0.803

NO3– + H2O + 2 e 1 NO2

– + 2 OH– 0.012 NO3

– + 2 H2O + 2 e 1 N2O4 + 4 OH– –0.85

Na+ + e 1 Na –2.71Nb3+ + 3 e 1 Nb –1.099NbO2 + 2 H+ + 2 e 1 NbO + H2O –0.646

NbO2 + 4 H+ + 4 e 1 Nb + 2 H2O –0.690NbO + 2 H+ + 2 e 1 Nb + H2O –0.733Nb2O5 + 10 H+ + 10 e 1 2 Nb + 5 H2O –0.644

Nd3+ + 3 e 1 Nd –2.323Nd2+ + 2 e 1 Nd –2.1Nd3+ + e 1 Nd2+ –2.7

Ni2+ + 2 e 1 Ni –0.257Ni(OH)2 + 2 e 1 Ni + 2 OH– –0.72NiO2 + 4 H+ + 2 e 1 Ni2+ + 2 H2O 1.678

NiO2 + 2 H2O + 2 e 1 Ni(OH)2 + 2 OH– –0.490No3+ + e 1 No2+ 1.4No3+ + 3 e 1 No –1.20

No2+ + 2 e 1 No –2.50Np3+ + 3 e 1 Np –1.856Np4+ + e 1 Np3+ 0.147

NpO2 + H2O + H+ + e 1 Np(OH)3 –0.962O2 + 2 H+ + 2 e 1 H2O2 0.695O2 + 4 H+ + 4 e 1 2 H2O 1.229

O2 + H2O + 2 e 1 HO2– + OH– –0.076

O2 + 2 H2O + 2 e 1 H2O2 + 2 OH– –0.146O2 + 2 H2O + 4 e 1 4 OH– 0.401

O3 + 2 H+ + 2 e 1 O2 + H2O 2.076O3 + H2O + 2 e 1 O2 + 2 OH– 1.24O(g) + 2 H+ + 2 e 1 H2O 2.421

OH + e 1 OH– 2.02HO2

– + H2O + 2 e 1 3 OH– 0.878OsO4 + 8 H+ + 8 e 1 Os + 4 H2O 0.838

OsO4 + 4 H+ + 4 e 1 OsO2 + 2 H2O 1.02[Os(bipy)2]3+ + e 1 [Os(bipy)2]

2+ 0.81[Os(bipy)3]3+ + e 1 [Os(bipy)3]

2+ 0.80

P(red) + 3 H+ + 3 e 1 PH3(g) –0.111P(white) + 3 H+ + 3 e 1 PH3(g) –0.063P + 3 H2O + 3 e 1 PH3(g) + 3 OH– –0.87

H2P2– + e 1 P + 2 OH– –1.82

H3PO2 + H+ + e 1 P + 2 H2O –0.508H3PO3 + 2 H+ + 2 e 1 H3PO2 + H2O –0.499H3PO3 + 3 H+ + 3 e 1 P + 3 H2O –0.454

HPO32– + 2 H2O + 2 e 1 H2PO2

– + 3 OH– –1.65HPO3

2– + 2 H2O + 3 e 1 P + 5 OH– –1.71H3PO4 + 2 H+ + 2 e 1 H3PO3 + H2O –0.276

PO43– + 2 H2O + 2 e 1 HPO3

2– + 3 OH– –1.05Pa3+ + 3 e 1 Pa –1.34Pa4+ + 4 e 1 Pa –1.49

Pa4+ + e 1 Pa3+ –1.9Pb2+ + 2 e 1 Pb –0.1262Pb2+ + 2 e 1 Pb(Hg) –0.1205

PbBr2 + 2 e 1 Pb + 2 Br– –0.284PbCl2 + 2 e 1 Pb + 2 Cl– –0.2675PbF2 + 2 e 1 Pb + 2 F– –0.3444

PbHPO4 + 2 e 1 Pb + HPO42– –0.465

PbI2 + 2 e 1 Pb + 2 I– –0.365PbO + H2O + 2 e 1 Pb + 2 OH– –0.580

PbO2 + 4 H+ + 2 e 1 Pb2+ + 2 H2O 1.455HPbO2

– + H2O + 2 e 1 Pb + 3 OH– –0.537PbO2 + H2O + 2 e 1 PbO + 2 OH– 0.247

PbO2 + SO42– + 4 H+ + 2 e 1 PbSO4 + 2 H2O 1.6913

PbSO4 + 2 e 1 Pb + SO42– –0.3588

PbSO4 + 2 e 1 Pb(Hg) + SO42– –0.3505

Pd2+ + 2 e 1 Pd 0.951[PdCl4]2– + 2 e 1 Pd + 4 Cl– 0.591[PdCl6]2– + 2 e 1 [PdCl4]

2– + 2 Cl– 1.288

Pd(OH)2 + 2 e 1 Pd + 2 OH– 0.07Pm2+ + 2 e 1 Pm –2.2Pm3+ + 3 e 1 Pm –2.30

Pm3+ + e 1 Pm2+ –2.6Po4+ + 2 e 1 Po2+ 0.9Po4+ + 4 e 1 Po 0.76

Pr4+ + e 1 Pr3+ 3.2Pr2+ + 2 e 1 Pr –2.0Pr3+ + 3 e 1 Pr –2.353

Pr3+ + e 1 Pr2+ –3.1Pt2+ + 2 e 1 Pt 1.18[PtCl4]

2– + 2 e 1 Pt + 4 Cl– 0.755

[PtCl6]2– + 2 e 1 [PtCl4]

2– + 2 Cl– 0.68Pt(OH)2 + 2 e 1 Pt + 2 OH– 0.14PtO3 + 2 H+ + 2 e 1 PtO2 + H2O 1.7

PtO3 + 4 H+ + 2 e 1 Pt(OH)22+ + H2O 1.5

PtOH+ + H+ + 2 e 1 Pt + H2O 1.2PtO2 + 2 H+ + 2 e 1 PtO + H2O 1.01

PtO2 + 4 H+ + 4 e 1 Pt + 2 H2O 1.00Pu3+ + 3 e 1 Pu –2.031Pu4+ + e 1 Pu3+ 1.006

Pu5+ + e 1 Pu4+ 1.099PuO2(OH)2 + 2 H+ + 2 e 1 Pu(OH)4 1.325PuO2(OH)2 + H+ + e 1 PuO2OH + H2O 1.062

Ra2+ + 2 e 1 Ra –2.8Rb+ + e 1 Rb –2.98Re3+ + 3 e 1 Re 0.300

Reaction E°/V Reaction E°/V




ReO4– + 4 H+ + 3 e 1 ReO2 + 2 H2O 0.510

ReO2 + 4 H+ + 4 e 1 Re + 2 H2O 0.2513ReO4

– + 2 H+ + e 1 ReO3 + H2O 0.768ReO4

– + 4 H2O + 7 e 1 Re + 8 OH– –0.584

ReO4– + 8 H+ + 7 e 1 Re + 4 H2O 0.368

Rh+ + e 1 Rh 0.600Rh+ + 2e1 Rh 0.600

Rh3+ + 3 e 1 Rh 0.758[RhCl6]

3– + 3 e 1 Rh + 6 Cl– 0.431RhOH2+ + H+ + 3 e 1 Rh + H2O 0.83

Ru2+ + 2 e 1 Ru 0.455Ru3+ + e 1 Ru2+ 0.2487RuO2 + 4 H+ + 2 e 1 Ru2+ + 2 H2O 1.120

RuO4– + e 1 RuO4

2– 0.59RuO4 + e 1 RuO4

– 1.00RuO4 + 6 H+ + 4 e 1 Ru(OH)2

2+ + 2 H2O 1.40

RuO4 + 8 H+ + 8 e 1 Ru + 4 H2O 1.038[Ru(bipy)3)

3+ + e–1 [Ru(bipy)3]2+ 1.24

[Ru(H2O)6]3+ + e–

1 [Ru(H2O)6]2+ 0.23

[Ru(NH3)6]3+ + e–

1 [Ru(NH3)6]2+ 0.10

[Ru(en)3]3+ + e –1 [Ru(en)3]2+ 0.210

[Ru(CN)6]3– + e–

1 [Ru(CN)6]4– 0.86

S + 2 e 1 S2– –0.47627S + 2H+ + 2 e 1 H2S(aq) 0.142S + H2O + 2 e 1 SH– + OH– –0.478

2 S + 2 e 1 S22– –0.42836

S2O62– + 4 H+ + 2 e 1 2 H2SO3 0.564

S2O82– + 2 e 1 2 SO4

2– 2.010

S2O82– + 2 H+ + 2 e 1 2 HSO4

– 2.123S4O6

2– + 2 e 1 2 S2O32– 0.08

2 H2SO3 + H+ + 2 e 1 HS2O4– + 2 H2O –0.056

H2SO3 + 4 H+ + 4 e 1 S + 3 H2O 0.4492 SO3

2– + 2 H2O + 2 e 1 S2O42– + 4 OH– –1.12

2 SO32– + 3 H2O + 4 e 1 S2O3

2– + 6 OH– –0.571

SO42– + 4 H+ + 2 e 1 H2SO3 + H2O 0.172

2 SO42– + 4 H+ + 2 e 1 S2O6

2– + H2O –0.22SO4

2– + H2O + 2 e 1 SO32– + 2 OH– –0.93

Sb + 3 H+ + 3 e 1 SbH3 –0.510Sb2O3 + 6 H+ + 6 e 1 2 Sb + 3 H2O 0.152Sb2O5 (senarmontite) + 4 H+ + 4 e 1 Sb2O3 + 2 H2O 0.671

Sb2O5 (valentinite) + 4 H+ + 4 e 1 Sb2O3 + 2 H2O 0.649Sb2O5 + 6 H+ + 4 e 1 2 SbO+ + 3 H2O 0.581SbO+ + 2 H+ + 3 e 1 Sb + 2 H2O 0.212

SbO2– + 2 H2O + 3 e 1 Sb + 4 OH– –0.66

SbO3– + H2O + 2 e 1 SbO2

– + 2 OH– –0.59Sc3+ + 3 e 1 Sc –2.077

Se + 2 e 1 Se2– –0.924Se + 2 H+ + 2 e 1 H2Se(aq) –0.399H2SeO3 + 4 H+ + 4 e 1 Se + 3 H2O 0.74

Se + 2 H+ + 2 e 1 H2Se –0.082SeO3

2– + 3 H2O + 4 e 1 Se + 6 OH– –0.366SeO4

2– + 4 H+ + 2 e 1 H2SeO3 + H2O 1.151

SeO42– + H2O + 2 e 1 SeO3

2– + 2 OH– 0.05SiF6

2– + 4 e 1 Si + 6 F– –1.24SiO + 2 H+ + 2 e 1 Si + H2O –0.8

SiO2 (quartz) + 4 H+ + 4 e 1 Si + 2 H2O 0.857

SiO32– + 3 H2O + 4 e 1 Si + 6 OH– –1.697

Sm3+ + e 1 Sm2+ –1.55Sm3+ + 3 e 1 Sm –2.304

Sm2+ + 2 e 1 Sm –2.68Sn2+ + 2 e 1 Sn –0.1375Sn4+ + 2 e 1 Sn2+ 0.151

Sn(OH)3+ + 3 H+ + 2 e 1 Sn2+ + 3 H2O 0.142

SnO2 + 4 H+ + 2 e–1 Sn2+ + 2 H2O –0.094

SnO2 + 4 H+ + 4 e 1 Sn + 2 H2O –0.117

SnO2 + 3 H+ + 2 e 1 SnOH+ + H2O –0.194SnO2 + 2 H2O + 4 e 1 Sn + 4 OH– –0.945HSnO2

– + H2O + 2 e 1 Sn + 3 OH– –0.909

Sn(OH)62– + 2 e 1 HSnO2

– + 3 OH– + H2O –0.93Sr+ + e 1 Sr –4.10Sr2+ + 2 e 1 Sr –2.899

Sr2+ + 2 e 1 Sr(Hg) –1.793Sr(OH)2 + 2 e 1 Sr + 2 OH– –2.88Ta2O5 + 10 H+ + 10 e 1 2 Ta + 5 H2O –0.750

Ta3+ + 3 e 1 Ta –0.6Tc2+ + 2 e 1 Tc 0.400TcO4

– + 4 H+ + 3 e 1 TcO2 + 2 H2O 0.782

Tc3+ + e 1 Tc2+ 0.3TcO4

– + 8 H+ + 7 e 1 Tc + 4 H2O 0.472Tb4+ + e 1 Tb3+ 3.1

Tb3+ + 3 e 1 Tb –2.28Te + 2 e 1 Te2– –1.143Te + 2 H+ + 2 e 1 H2Te –0.793

Te4+ + 4 e 1 Te 0.568TeO2 + 4 H+ + 4 e 1 Te + 2 H2O 0.593TeO3

2– + 3 H2O + 4 e 1 Te + 6 OH– –0.57

TeO4– + 8 H+ + 7 e 1 Te + 4 H2O 0.472

H6TeO6 + 2 H+ + 2 e 1 TeO2 + 4 H2O 1.02Th4+ + 4 e 1 Th –1.899

ThO2 + 4 H+ + 4 e 1 Th + 2 H2O –1.789Th(OH)4 + 4 e 1 Th + 4 OH– –2.48Ti2+ + 2 e 1 Ti –1.630

Ti3+ + e 1 Ti2+ –0.9TiO2 + 4 H+ + 2 e 1 Ti2+ + 2 H2O –0.502Ti3+ + 3 e 1 Ti –1.37

TiOH3+ + H+ + e 1 Ti3+ + H2O –0.055Tl+ + e 1 Tl –0.336Tl+ + e 1 Tl(Hg) –0.3338

Tl3+ + 2 e 1 Tl+ 1.252Tl3+ + 3 e 1 Tl 0.741TlBr + e 1 Tl + Br– –0.658

TlCl + e 1 Tl + Cl– –0.5568TlI + e 1 Tl + I– –0.752Tl2O3 + 3 H2O + 4 e 1 2 Tl+ + 6 OH– 0.02

TlOH + e 1 Tl + OH– –0.34Tl(OH)3 + 2 e 1 TlOH + 2 OH– –0.05Tl2SO4 + 2 e 1 Tl + SO4

2– –0.4360

Tm3+ + e 1 Tm2+ –2.2Tm3+ + 3 e 1 Tm –2.319Tm2+ + 2 e 1 Tm –2.4




U3+ + 3 e 1 U –1.798

U4+ + e 1 U3+ –0.607UO2

+ + 4 H+ + e 1 U4+ + 2 H2O 0.612UO2

2+ + e 1 UO+2 0.062

UO22+ + 4 H+ + 2 e 1 U4+ + 2 H2O 0.327

UO22+ + 4 H+ + 6 e 1 U + 2 H2O –1.444

V2+ + 2 e 1 V –1.175

V3+ + e 1 V2+ –0.255VO2+ + 2 H+ + e 1 V3+ + H2O 0.337VO2

+ + 2 H+ + e 1 VO2+ + H2O 0.991

V2O5 + 6 H+ + 2 e 1 2 VO2+ + 3 H2O 0.957V2O5 + 10 H+ + 10 e 1 2 V + 5 H2O –0.242V(OH)4

+ + 2 H+ + e 1 VO2+ + 3 H2O 1.00

V(OH)4+ + 4 H+ + 5 e 1 V + 4 H2O –0.254

[V(phen)3]3+ + e 1 [V(phen)3]2+ 0.14

W3+ + 3 e 1 W 0.1

W2O5 + 2 H+ + 2 e 1 2 WO2 + H2O –0.031WO2 + 4 H+ + 4 e 1 W + 2 H2O –0.119WO3 + 6 H+ + 6 e 1 W + 3 H2O –0.090

WO3 + 2 H+ + 2 e 1 WO2 + H2O 0.036

2 WO3 + 2 H+ + 2 e 1 W2O5 + H2O –0.029

H4XeO6 + 2 H+ + 2 e 1 XeO3 + 3 H2O 2.42XeO3 + 6 H+ + 6 e 1 Xe + 3 H2O 2.10XeF + e 1 Xe + F– 3.4

Y3+ + 3 e 1 Y –2.372Yb3+ + e 1 Yb2+ –1.05Yb3+ + 3 e 1 Yb –2.19

Yb2+ + 2 e 1 Yb –2.76Zn2+ + 2 e 1 Zn –0.7618Zn2+ + 2 e 1 Zn(Hg) –0.7628

ZnO22– + 2 H2O + 2 e 1 Zn + 4 OH– –1.215

ZnSO4 ⋅ 7 H2O + 2 e = Zn(Hg) + SO42– + 7 H2O –0.7993

(Saturated ZnSO4)

ZnOH+ + H+ + 2 e 1 Zn + H2O –0.497Zn(OH)4

2– + 2 e 1 Zn + 4 OH– –1.199Zn(OH)2 + 2 e 1 Zn + 2 OH– –1.249

ZnO + H2O + 2 e 1 Zn + 2 OH– –1.260ZrO2 + 4 H+ + 4 e 1 Zr + 2 H2O –1.553ZrO(OH)2 + H2O + 4 e 1 Zr + 4 OH– –2.36

Zr4+ + 4 e 1 Zr –1.45


TABLE 2Reduction Reactions Having E° Values More Positive than that of the Standard Hydrogen Electrode

Reaction E°/V

2 H+ + 2 e 1 H2 0.00000CuI2

– + e 1 Cu + 2 I– 0.00

Ge4+ + 2 e 1 Ge2+ 0.00NO3

– + H2O + 2 e 1 NO2– + 2 OH– 0.01

Tl2O3 + 3 H2O + 4 e 1 2 Tl+ + 6 OH– 0.02

SeO42– + H2O + 2 e 1 SeO3

2– + 2 OH– 0.05WO3 + 2 H+ + 2 e 1 WO2 + H2O 0.036UO2

2+ + e = UO2+ 0.062

Pd(OH)2 + 2 e 1 Pd + 2 OH– 0.07AgBr + e 1 Ag + Br– 0.07133MoO3 + 6 H+ + 6 e 1 Mo + 3 H2O 0.075

S4O62– + 2 e 1 2 S2O3

2– 0.08H3Mo7O24

3– + 45 H+ + 42 e 1 7 Mo + 24 H2O 0.082AgSCN + e 1 Ag + SCN– 0.8951

N2 + 2 H2O + 6 H+ + 6 e 1 2 NH4OH 0.092HgO + H2O + 2 e 1 Hg + 2 OH– 0.0977Ir2O3 + 3 H2O + 6 e 1 2 Ir + 6 OH– 0.098

2 NO + 2 e 1 N2O22– 0.10

[Ru(NH3)6]3+ + e 1 [Ru(NH3)6]2+ 0.10

W3+ + 3 e 1 W 0.1

[Co(NH3)6]3+ + e 1 [Co(NH3)6]2+ 0.108

Hg2O + H2O + 2 e 1 2 Hg + 2 OH– 0.123Ge4+ + 4 e 1 Ge 0.124

Hg2Br2 + 2 e 1 2 Hg + 2 Br– 0.13923Pt(OH)2 + 2 e 1 Pt + 2 OH– 0.14[V(phen)3]3+ + e 1 [V(phen)3]

2+ 0.14

S + 2H+ + 2 e 1 H2S(aq) 0.142

Sn(OH)3+ + 3 H+ + 2 e 1 Sn2+ + 3 H2O 0.142

Np4+ + e 1 Np3+ 0.147Ag4[Fe(CN)6] + 4 e 1 4 Ag + [Fe(CN)6]

4– 0.1478

IO3– + 2 H2O + 4 e 1 IO– + 4 OH– 0.15

Mn(OH)3 + e 1 Mn(OH)2 + OH– 0.152 NO2

– + 3 H2O + 4 e 1 N2O + 6 OH– 0.15

Sn4+ + 2 e 1 Sn2+ 0.151Sb2O3 + 6 H+ + 6 e 1 2 Sb + 3 H2O 0.152Cu2+ + e 1 Cu+ 0.153

BiOCl + 2 H+ + 3 e 1 Bi + Cl– + H2O 0.1583BiCl4

– + 3 e 1 Bi + 4 Cl– 0.16Fe2O3 + 4 H+ + 2 e 1 2 FeOH+ + H2O 0.16

Co(OH)3 + e 1 Co(OH)2 + OH– 0.17SO4

2– + 4 H+ + 2 e 1 H2SO3 + H2O 0.172Bi3+ + 2 e 1 Bi+ 0.2

[Ru(en)3]3+ + e 1 [Ru(en)3]

2+ 0.210SbO+ + 2 H+ + 3 e 1 Sb + 2 H2O 0.212AgCl + e 1 Ag + Cl– 0.22233

[Ru(H2O)6]3+ + e 1 [Ru(H2O)6]2+ 0.23

As2O3 + 6 H+ + 6 e 1 2 As + 3 H2O 0.234Calomel electrode, saturated NaCl (SSCE) 0.2360

Ge2+ + 2 e 1 Ge 0.24Ru3+ + e 1 Ru2+ 0.24Calomel electrode, saturated KCl 0.2412

PbO2 + H2O + 2 e 1 PbO + 2 OH– 0.247HAsO2 + 3 H+ + 3 e 1 As + 2 H2O 0.248Ru3+ + e 1 Ru2+ 0.2487

Reaction E°/V Reaction E°/V

Reaction E°/V


5-90

MOLAR CONDUCTIVITY OF AQUEOUS HF, HCl, HBr, AND HI

The molar conductivity Λ of an electrolyte solution is defined as the conductivity divided by amount-of-substance concentration. The customary

unit is S cm2mol-1 (i.e., Ω-1 cm2mol-1). The first part of this table gives the molar conductivity of the hydrohalogen acids at 25°C as a function of theconcentration in mol/L. The second part gives the temperature dependence of Λ for HCl and HBr. More extensive tables and mathematicalrepresentations may be found in the reference.

REFERENCE

Hamer, W.J., and DeWane, H.J., Electrolytic Conductance and the Conductances of the Hydrohalogen Acids in Water, Natl. Stand. Ref. Data Sys.-Natl. Bur. Standards (U.S.), No. 33, 1970.

c/mol L–1 HF HCl HBr HI

Inf. dil. 405.1 426.1 427.7 426.40.0001 424.5 425.9 424.60.0005 422.6 424.3 423.0

0.001 421.2 422.9 421.70.005 128.1 415.7 417.6 416.40.01 96.1 411.9 413.7 412.8

0.05 50.1 398.9 400.4 400.80.10 39.1 391.1 391.9 394.00.5 26.3 360.7 361.9 369.8

1.0 24.3 332.2 334.5 343.91.5 305.8 307.6 316.42.0 281.4 281.7 288.9

2.5 258.9 257.8 262.53.0 237.6 236.8 237.9

3.5 218.3 217.5 215.44.0 200.0 199.4 195.14.5 183.1 182.4 176.8

5.0 167.4 166.5 160.45.5 152.9 151.8 145.56.0 139.7 138.2 131.7

6.5 127.7 125.7 118.67.0 116.9 114.2 105.77.5 107.0 103.8

8.0 98.2 94.48.5 90.3 85.89.0 83.1

9.5 76.610.0 70.7

c/mol L–1 HF HCl HBr HI

c/mol L–1 –20°C –10°C 0°C 10°C 20°C 30°C 40°C 50°C

HCl

0.5 228.7 283.0 336.4 386.8 436.9 482.41.0 211.7 261.6 312.2 359.0 402.9 445.3

1.5 196.2 241.5 287.5 331.1 371.6 410.82.0 182.0 222.7 262.9 303.3 342.4 378.22.5 131.7 168.5 205.1 239.8 277.0 315.2 347.6

3.0 120.8 154.6 188.5 219.3 253.3 289.3 319.03.5 85.5 111.3 139.6 172.2 201.6 232.9 263.9 292.14.0 79.3 102.7 129.2 158.1 185.6 214.2 242.2 268.2

4.5 73.7 94.9 119.5 145.4 170.6 196.6 222.5 246.75.0 68.5 87.8 110.3 133.5 156.6 180.2 204.1 226.55.5 63.6 81.1 101.7 122.5 143.6 165.0 187.1 207.7

6.0 58.9 74.9 93.7 112.3 131.5 151.0 171.3 190.36.5 54.4 69.1 86.2 103.0 120.4 138.2 156.9 174.37.0 50.2 63.7 79.3 94.4 110.2 126.4 143.3 159.7

7.5 46.3 58.6 73.0 86.5 100.9 115.7 131.6 146.28.0 42.7 54.0 67.1 79.4 92.4 106.1 120.6 134.08.5 39.4 49.8 61.7 72.9 84.7 97.3 110.7 123.0

9.0 36.4 45.9 56.8 67.1 77.8 89.4 101.7 112.99.5 33.6 42.3 52.3 61.8 71.5 82.3 93.6 103.9

10.0 31.2 39.1 48.2 57.0 65.8 75.9 86.3 95.7

10.5 28.9 36.1 44.5 52.7 60.7 70.1 79.6 88.411.0 26.8 33.4 41.1 48.8 56.1 64.9 73.6 81.711.5 24.9 31.0 38.0 45.3 51.9 60.1 68.0 75.6

12.0 23.1 28.7 35.3 42.0 48.0 55.6 62.8 70.012.5 21.4 26.7 32.7 39.0 44.4 51.4 57.9 64.8

5-91

MOLAR CONDUCTIVITY OF AQUEOUS HF, HCl, HBr, AND HI (continued)

c/mol L–1 –20°C –10°C 0°C 10°C 20°C 30°C 40°C 50°C

HBr

0.5 240.9 295.9 347.0 398.9 453.6 496.81.0 229.6 276.0 329.0 380.4 418.6 465.2

1.5 209.5 254.9 298.9 340.6 381.8 421.42.0 150.8 188.6 231.3 271.8 314.1 350.5 387.42.5 136.8 171.7 208.3 244.8 281.7 316.0 349.1

3.0 125.7 157.2 189.5 222.2 255.0 287.8 318.63.5 116.1 144.1 174.6 203.2 234.4 263.7 291.94.0 84.0 107.5 132.3 160.2 186.8 214.2 239.7 266.9

4.5 78.0 99.0 123.0 146.4 171.2 195.1 218.8 242.65.0 72.3 91.4 112.6 134.0 155.7 178.2 199.6 221.35.5 67.0 84.2 103.1 122.7 142.1 162.8 181.4 201.8

6.0 61.8 77.2 94.3 112.0 129.6 148.0 165.4 183.46.5 56.8 70.7 86.0 102.0 118.0 134.1 150.5 166.37.0 51.9 64.6 78.4 92.6 107.1 121.4 136.3 150.8

5-91

STANDARD KCl SOLUTIONS FOR CALIBRATING CONDUCTIVITY CELLS

This table presents recommended electrolytic conductivity (k) values for aqueous potassium chloride solutions with molalities of 0.01 mol/kg,

0.1 mol/kg and 1.0 mol/kg at temperatures from 0˚C to 50˚C. The values, which are based on measurements at the National Institute of Standards

and Technology, provide primary standards for the calibration of conductivity cells. The measurements at 0.01 and 0.1 molal are described in

Reference 1, while those at 1.0 molal are in Reference 2. Temperatures are given on the ITS-90 scale. The uncertainty in the conductivity is about

0.03% for the 0.01 molal values and about 0.04% for the 0.1 and 1.0 molal values. The conductivity of water saturated with atmospheric CO2 is

given in the last column. These values were subtracted from the original measurements to give the values in the second, third, and fourth

columns. All k values are given in units of 10-4 S/m (numerically equal to mS/cm).

The assistance of Kenneth W. Pratt is appreciated.

REFERENCES

1. Wu, Y.C., Koch, W.F., and Pratt, K.W., J. Res. Natl. Inst. Stand. Technol. 96, 191, 1991.

2. Wu, Y.C., Koch, W.F., Feng, D., Holland, L.A., Juhasz, E., Arvay, E., and Tomek, A., J. Res. Natl. Inst. Stand. Technol. 99, 241, 1994.

3. Pratt, K.W., Koch, W.F., Wu, Y.C., and Berezansky, P.A., Pure Appl. Chem. 73, 1783, 2001.

104 k/S m-1

t/˚C 0.01 m KCl 0.1 m KCl 1.0 m KCl H2O (CO2 sat.)

0 772.92 7 116.85 63 488 0.58

5 890.96 8 183.70 72 030 0.68

10 1 013.95 9 291.72 80 844 0.79

15 1 141.45 10 437.1 89 900 0.89

18 1 219.93 11 140.6 —- 0.95

20 1 273.03 11 615.9 99 170 0.99

25 1 408.23 12 824.6 108 620 1.10

30 1 546.63 14 059.2 118 240 1.20

35 1 687.79 15 316.0 127 970 1.30

40 1 831.27 16 591.0 137 810 1.40

45 1 976.62 17 880.6 147 720 1.51

50 2 123.43 19 180.9 157 670 1.61

5-92

EQUIVALENT CONDUCTIVITY OF ELECTROLYTES IN AQUEOUS SOLUTIONPetr Vanysek

Concentration (mol/L)

InfiniteCompound dilution 0.0005 0.001 0.005 0.01 0.02 0.05 0.1

Λ° Λ

AgNO3 133.29 131.29 130.45 127.14 124.70 121.35 115.18 109.09

1/2BaCl2 139.91 135.89 134.27 127.96 123.88 119.03 111.42 105.141/2CaCl2 135.77 131.86 130.30 124.19 120.30 115.59 108.42 102.411/2Ca(OH)2 258 — — 233 226 214 — —

1/2CuSO4 133.6 121.6 115.20 94.02 83.08 72.16 59.02 50.55HCl 425.95 422.53 421.15 415.59 411.80 407.04 398.89 391.13KBr 151.9 149.8 148.9 146.02 143.36 140.41 135.61 131.32

KCl 149.79 147.74 146.88 143.48 141.20 138.27 133.30 128.90KClO4 139.97 138.69 137.80 134.09 131.39 127.86 121.56 115.141/3K3Fe(CN)6 174.5 166.4 163.1 150.7 — — — —

1/4K4Fe(CN)6 184 — 167.16 146.02 134.76 122.76 107.65 97.82KHCO3 117.94 116.04 115.28 112.18 110.03 107.17 — —KI 150.31 148.2 143.32 144.30 142.11 139.38 134.90 131.05

KIO4 127.86 125.74 124.88 121.18 118.45 114.08 106.67 98.2KNO3 144.89 142.70 141.77 138.41 132.75 132.34 126.25 120.34KMnO4 134.8 132.7 131.9 — 126.5 — — 113

KOH 271.5 — 234 230 228 — 219 213KReO4 128.20 126.03 125.12 121.31 118.49 114.49 106.40 97.401/3LaCl3 145.9 139.6 137.0 127.5 121.8 115.3 106.2 99.1

LiCl 114.97 113.09 112.34 109.35 107.27 104.60 100.06 95.81LiClO4 105.93 104.13 103.39 100.52 98.56 96.13 92.15 88.521/2MgCl2 129.34 125.55 124.15 118.25 114.49 109.99 103.03 97.05

NH4Cl 149.6 147.5 146.7 134.4 141.21 138.25 133.22 128.69NaCl 126.39 124.44 123.68 120.59 118.45 115.70 111.01 106.69NaClO4 117.42 115.58 114.82 111.70 109.54 106.91 102.35 98.38

NaI 126.88 125.30 124.19 121.19 119.18 116.64 112.73 108.73NaOOCCH3 91.0 89.2 88.5 85.68 83.72 81.20 76.88 72.76NaOH 247.7 245.5 244.6 240.7 237.9 — — —

Na picrate 80.45 78.7 78.6 75.7 73.7 — 66.3 61.81/2Na2SO4 129.8 125.68 124.09 117.09 112.38 106.73 97.70 89.941/2SrCl2 135.73 131.84 130.27 124.18 120.23 115.48 108.20 102.14

1/2ZnSO4 132.7 121.3 114.47 95.44 84.87 74.20 61.17 52.61

This table gives the equivalent (molar) conductivity Λ at 25°C for some common electrolytes in aqueous solution at concentrations up to 0.1 mol/L. The units of Λ are 10–4 m2 S mol–1.

For very dilute solutions, the equivalent conductivity for any electrolyte of concentration c can be approximately calculated using the Debye-

Hückel-Onsager equation, which can be written for a symmetrical (equal charge on cation and anion) electrolyte as

Λ = Λ° – (A + BΛ°)c1/2

For a solution at 25°C and both cation and anion with charge *1*, the constants are A = 60.20 and B = 0.229. Λ° can be found from the next table, “IonicConductivity and Diffusion at Infinite Dilution”. The equation is reliable for c < 0.001 mol/L; with higher concentration the error increases.

IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTIONPetr Vanysek

This table gives the molar (equivalent) conductivity λ for common ions at infinite dilution. All values refer to aqueous solutions at 25°C. It also

lists the diffusion coefficient D of the ion in dilute aqueous solution, which is related to λ through the equation

where R is the molar gas constant, T the temperature, F the Faraday constant, and z the charge on the ion. The variation with temperature is fairly sharp;for typical ions, λ and D increase by 2 to 3% per degree as the temperature increases from 25°C.

The diffusion coefficient for a salt, Dsalt, may be calculated from the D+ and D– values of the constituent ions by the relation

For solutions of simple, pure electrolytes (one positive and one negative ionic species), such as NaCl, equivalent ionic conductivity Λ°, which is

the conductivity per unit concentration of charge, is defined as

where λ+ and λ– are equivalent ionic conductivities of the cation and anion. The more general formula is

Λ° = ν+λ+ + ν−λ−

where ν+ and ν− refer to the number of moles of cations and anions to which one mole of the electrolyte gives a rise in the solution.

REFERENCES

1. Gray, D. E., Ed., American Institute of Physics Handbook, McGraw-Hill, New York, 1972, 2—226.2. Robinson, R. A., and Stokes, R. H., Electrolyte Solutions, Butterworths, London, 1959.3. Lobo, V. M. M., and Quaresma, J. L., Handbook of Electrolyte Solutions, Physical Science Data Series 41, Elsevier, Amsterdam, 1989.

4. Conway, B. E., Electrochemical Data, Elsevier, Amsterdam, 1952.5. Milazzo, G., Electrochemistry: Theoretical Principles and Practical Applications, Elsevier, Amsterdam, 1963.

λ DIon 10-4 m2 S mol-1 10-5 cm2 s-1

Inorganic Cations

Ag+ 61.9 1.6481/3Al3+ 61 0.5411/2Ba2+ 63.6 0.847

1/2Be2+ 45 0.5991/2Ca2+ 59.47 0.7921/2Cd2+ 54 0.719

1/3Ce3+ 69.8 0.6201/2Co2+ 55 0.7321/3[Co(NH3)6]

3+ 101.9 0.904

1/3[Co(en)3]3+ 74.7 0.6631/6[Co2(trien)3]

6+ 69 0.3061/3Cr3+ 67 0.595

Cs+ 77.2 2.0561/2Cu2+ 53.6 0.714D+ 249.9 6.655

1/3Dy3+ 65.6 0.5821/3Er3+ 65.9 0.5851/3Eu3+ 67.8 0.602

1/2Fe2+ 54 0.7191/3Fe3+ 68 0.6041/3Gd3+ 67.3 0.597

H+ 349.65 9.3111/2Hg2+ 68.6 0.9131/2Hg2+ 63.6 0.847

λ DIon 10-4 m2 S mol-1 10-5 cm2 s-1

1/3Ho3+ 66.3 0.589K+ 73.48 1.957

1/3La3+ 69.7 0.619Li+ 38.66 1.0291/2Mg2+ 53.0 0.706

1/2Mn2+ 53.5 0.712NH4

+ 73.5 1.957N2H5

+ 59 1.571

Na+ 50.08 1.3341/3Nd3+ 69.4 0.6161/2Ni2+ 49.6 0.661

1/4[Ni2(trien)3]4+ 52 0.346

1/2Pb2+ 71 0.9451/3Pr3+ 69.5 0.617

1/2Ra2+ 66.8 0.889Rb+ 77.8 2.0721/3Sc3+ 64.7 0.574

1/3Sm3+ 68.5 0.6081/2Sr2+ 59.4 0.791Tl+ 74.7 1.989

1/3Tm3+ 65.4 0.5811/2UO2

2+ 32 0.4261/3Y3+ 62 0.550

1/3Yb3+ 65.6 0.5821/2Zn2+ 52.8 0.703

Λ° = ++λ λ–

Dz z D D

z D z Dsalt =

+( )+

+ +

+ +

– –

– –

D RT F z= ( )( )/ /2 λ


IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION (continued)

λ D

Ion 10-4 m2 S mol-1 10-5 cm2 s-1

λ D

Ion 10-4 m2 S mol-1 10-5 cm2 s-1

Inorganic Anions

Au(CN)2- 50 1.331

Au(CN)4- 36 0.959

B(C6H5)4- 21 0.559

Br- 78.1 2.080Br3

- 43 1.145

BrO3- 55.7 1.483

CN- 78 2.077CNO- 64.6 1.720

1/2CO32- 69.3 0.923

Cl- 76.31 2.032ClO2

- 52 1.385

ClO3- 64.6 1.720

ClO4- 67.3 1.792

1/3[Co(CN)6]3- 98.9 0.878

1/2CrO42- 85 1.132

F- 55.4 1.4751/4[Fe(CN)6]

4- 110.4 0.735

1/3[Fe(CN)6]3- 100.9 0.896

H2AsO4- 34 0.905

HCO3- 44.5 1.185

HF2- 75 1.997

1/2HPO42- 57 0.759

H2PO4- 36 0.959

H2PO2- 46 1.225

HS- 65 1.731HSO3

- 58 1.545

HSO4- 52 1.385

H2SbO4- 31 0.825

I- 76.8 2.045

IO3- 40.5 1.078

IO4- 54.5 1.451

MnO4- 61.3 1.632

1/2MoO42- 74.5 1.984

N(CN)2- 54.5 1.451

NO2- 71.8 1.912

NO3- 71.42 1.902

NH2SO3- 48.3 1.286

N3- 69 1.837

OCN- 64.6 1.720OD- 119 3.169OH- 198 5.273

PF6- 56.9 1.515

1/2PO3F2- 63.3 0.843

1/3PO43- 92.8 0.824

1/4P2O74- 96 0.639

1/3P3O93- 83.6 0.742

1/5P3O105- 109 0.581

ReO4- 54.9 1.462

SCN- 66 1.7581/2SO3

2- 72 0.959

1/2SO42- 80.0 1.065

1/2S2O32- 85.0 1.132

1/2S2O42- 66.5 0.885

1/2S2O62- 93 1.238

1/2S2O82- 86 1.145

Sb(OH)6- 31.9 0.849

SeCN- 64.7 1.723

1/2SeO42- 75.7 1.008

1/2WO42- 69 0.919

Organic Cations

Benzyltrimethylammonium+ 34.6 0.921Isobutylammonium+ 38 1.012

Butyltrimethylammonium+ 33.6 0.895Decylpyridinium+ 29.5 0.786Decyltrimethylammonium+ 24.4 0.650

Diethylammonium+ 42.0 1.118Dimethylammonium+ 51.8 1.379Dipropylammonium+ 30.1 0.802

Dodecylammonium+ 23.8 0.634Dodecyltrimethylammonium+ 22.6 0.602Ethanolammonium+ 42.2 1.124

Ethylammonium+ 47.2 1.257Ethyltrimethylammonium+ 40.5 1.078Hexadecyltrimethylammonium+ 20.9 0.557

Hexyltrimethylammonium+ 29.6 0.788Histidyl+ 23.0 0.612Hydroxyethyltrimethylarsonium+ 39.4 1.049

Methylammonium+ 58.7 1.563Octadecylpyridinium+ 20 0.533Octadecyltributylammonium+ 16.6 0.442

Octadecyltriethylammonium+ 17.9 0.477Octadecyltrimethylammonium+ 19.9 0.530Octadecyltripropylammonium+ 17.2 0.458

Octyltrimethylammonium+ 26.5 0.706Pentylammonium+ 37 0.985Piperidinium+ 37.2 0.991

Propylammonium+ 40.8 1.086Pyrilammonium+ 24.3 0.647Tetrabutylammonium+ 19.5 0.519

Tetradecyltrimethylammonium+ 21.5 0.573Tetraethylammonium+ 32.6 0.868Tetramethylammonium+ 44.9 1.196

Tetraisopentylammonium+ 17.9 0.477Tetrapentylammmonium+ 17.5 0.466Tetrapropylammonium+ 23.4 0.623

Triethylammonium+ 34.3 0.913Triethylsulfonium+ 36.1 0.961Trimethylammonium+ 47.23 1.258

Trimethylhexylammonium+ 34.6 0.921Trimethylsulfonium+ 51.4 1.369Tripropylammonium+ 26.1 0.695

Organic Anions

Acetate- 40.9 1.089p-Anisate- 29.0 0.7721/2Azelate2- 40.6 0.541

Benzoate- 32.4 0.863Bromoacetate- 39.2 1.044Bromobenzoate- 30 0.799

Butyrate- 32.6 0.868Chloroacetate- 39.8 1.060m-Chlorobenzoate- 31 0.825

o-Chlorobenzoate- 30.2 0.804


IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION (continued)

λ D

Ion 10-4 m2 S mol-1 10-5 cm2 s-1

λ D

Ion 10-4 m2 S mol-1 10-5 cm2 s-1

1/3Citrate3- 70.2 0.623

Crotonate- 33.2 0.884Cyanoacetate- 43.4 1.156Cyclohexane carboxylate- 28.7 0.764

1/2 1,1-Cyclopropanedicarboxylate2- 53.4 0.711Decylsulfate- 26 0.692Dichloroacetate- 38.3 1.020

1/2Diethylbarbiturate2- 26.3 0.350Dihydrogencitrate- 30 0.7991/2Dimethylmalonate2- 49.4 0.658

3,5-Dinitrobenzoate- 28.3 0.754Dodecylsulfate- 24 0.639Ethylmalonate- 49.3 1.313

Ethylsulfate- 39.6 1.055Fluoroacetate- 44.4 1.182Fluorobenzoate- 33 0.879

Formate- 54.6 1.4541/2Fumarate2- 61.8 0.8231/2Glutarate2- 52.6 0.700

Hydrogenoxalate- 40.2 1.070Isovalerate- 32.7 0.871

Iodoacetate- 40.6 1.081

Lactate- 38.8 1.0331/2Malate2- 58.8 0.7831/2Maleate2- 61.9 0.824

1/2Malonate2- 63.5 0.845Methylsulfate- 48.8 1.299Naphthylacetate- 28.4 0.756

1/2Oxalate2- 74.11 0.987Octylsulfate- 29 0.772Phenylacetate- 30.6 0.815

1/2o-Phthalate2- 52.3 0.6961/2m-Phthalate2- 54.7 0.728Picrate- 30.37 0.809

Pivalate- 31.9 0.849Propionate- 35.8 0.953Propylsulfate- 37.1 0.988

Salicylate- 36 0.9591/2Suberate2- 36 0.4791/2Succinate2- 58.8 0.783

p-Sulfonate 29.3 0.7801/2Tartarate2- 59.6 0.794Trichloroacetate- 35 0.932


Tablas i Ones

Documents

Transcript of Tablas i Ones