ELECTROCHEMICAL SERIES. Petr Vanýsek

ELECTROCHEMICAL SERIES Petr Vanýsek 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) precedes those for aluminum (Al). Table 2 lists only those reduction reactions which have E values positive in respect to the standard hydrogen electrode. In Table 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 potential and 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 figures have 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 1 Alphabetical Listing Ac 3+ + 3 e 1 Ac 2.20 Ag + + e 1 Ag 0.7996 Ag 2+ + e 1 Ag + 1.980 Ag(ac) + e 1 Ag + (ac) 0.643 AgBr + e 1 Ag + Br 0.07133 AgBrO 3 + e 1 Ag + BrO 3 0.546 Ag 2 C 2 O 4 + 2 e 1 2 Ag + C 2 O 2 4 0.4647 AgCl + e 1 Ag + Cl 0.22233 AgCN + e 1 Ag + CN 0.017 Ag 2 CO 3 + 2 e 1 2 Ag + CO 2 3 0.47 Ag 2 CrO 4 + 2 e 1 2 Ag + CrO 2 4 0.4470 AgF + e 1 Ag + F 0.779 Ag 4 [Fe(CN) 6 ] + 4 e 1 4 Ag + [Fe(CN) 6 ] 4 0.1478 AgI + e 1 Ag + I 0.15224 AgIO 3 + e 1 Ag + IO 3 0.354 Ag 2 MoO 4 + 2 e 1 2 Ag + MoO 2 4 0.4573 Ag 2 + e 1 Ag + 2 2 0.564 Ag 2 O + H 2 O + 2 e 1 2 Ag + 2 OH 0.342 Ag 2 O 3 + H 2 O + 2 e 1 2 AgO + 2 OH 0.739 Ag 3+ + 2 e 1 Ag + 1.9 Ag 3+ + e 1 Ag 2+ 1.8 Ag 2 O 2 + 4 H + + e 1 2 Ag + 2 H 2 O 1.802 2 AgO + H 2 O + 2 e 1 Ag 2 O + 2 OH 0.607 AgOCN + e 1 Ag + OCN 0.41 Ag 2 S + 2 e 1 2 Ag + S 2 0.691 Ag 2 S + 2 H + + 2 e 1 2 Ag + H 2 S 0.0366 AgSCN + e 1 Ag + SCN 0.08951 Ag 2 SeO 3 + 2 e 1 2 Ag + SeO 2 4 0.3629 Ag 2 SO 4 + 2 e 1 2 Ag + SO 2 4 0.654 Ag 2 WO 4 + 2 e 1 2 Ag + WO 2 4 0.4660 Al 3+ + 3 e 1 Al 1.662 Al(OH) 3 + 3 e 1 Al + 3 OH 2.31 Al(OH) 4 + 3 e 1 Al + 4 OH 2.328 H 2 AlO 3 + H 2 O + 3 e 1 Al + 4 OH 2.33 AlF 3 6 + 3 e 1 Al + 6 F 2.069 Am 4+ + e 1 Am 3+ 2.60 Am 2+ + 2 e 1 Am 1.9 Am 3+ + 3 e 1 Am 2.048 Am 3+ + e 1 Am 2+ 2.3 As + 3 H + + 3 e 1 AsH 3 0.608 As 2 O 3 + 6 H + + 6 e 1 2 As + 3 H 2 O 0.234 HAsO 2 + 3 H + + 3 e 1 As + 2 H 2 O 0.248 AsO 2 + 2 H 2 O + 3 e 1 As + 4 OH 0.68 H 3 AsO 4 + 2 H + + 2 e 1 HAsO 2 + 2 H 2 O 0.560 AsO 3 4 + 2 H 2 O + 2 e 1 AsO 2 + 4 OH 0.71 At 2 + 2 e 1 2 At 0.3 Au + + e 1 Au 1.692 Au 3+ + 2 e 1 Au + 1.401 Au 3+ + 3 e 1 Au 1.498 Au 2+ + e 1 Au + 1.8 AuOH 2+ + H + + 2 e 1 Au + + H 2 O 1.32 AuBr 2 + e 1 Au + 2 Br 0.959 AuBr 4 + 3 e 1 Au + 4 Br 0.854 AuCl 4 + 3 e 1 Au + 4 Cl 1.002 Au(OH) 3 + 3 H + + 3 e 1 Au + 3 H 2 O 1.45 H 2 BO 3 + 5 H 2 O + 8 e 1 BH 4 + 8 OH 1.24 H 2 BO 3 + H 2 O + 3 e 1 B + 4 OH 1.79 H 3 BO 3 + 3 H + + 3 e 1 B + 3 H 2 O 0.8698 B(OH) 3 + 7 H + + 8 e 1 BH 4 + 3 H 2 O 0.481 Ba 2+ + 2 e 1 Ba 2.912 Ba 2+ + 2 e 1 Ba(Hg) 1.570 Ba(OH) 2 + 2 e 1 Ba + 2 OH 2.99 Be 2+ + 2 e 1 Be 1.847 Be 2 O 2 3 + 3 H 2 O + 4 e 1 2 Be + 6 OH 2.63

ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) p benzoquinone + 2 H + + 2 e 1 hydroquinone 0.6992 Bi + + e 1 Bi 0.5 Bi 3+ + 3 e 1 Bi 0.308 Bi 3+ + 2 e 1 Bi + 0.2 Bi + 3 H + + 3 e 1 BiH 3 0.8 BiCl 4 + 3 e 1 Bi + 4 Cl 0.16 Bi 2 O 3 + 3 H 2 O + 6 e 1 2 Bi + 6 OH 0.46 Bi 2 O 4 + 4 H + + 2 e 1 2 BiO + + 2 H 2 O 1.593 BiO + + 2 H + + 3 e 1 Bi + H 2 O 0.320 BiOCl + 2 H + + 3 e 1 Bi + Cl + H 2 O 0.1583 Bk 4+ + e 1 Bk 3+ 1.67 Bk 2+ + 2 e 1 Bk 1.6 Bk 3+ + e 1 Bk 2+ 2.8 Br 2 (aq) + 2 e 1 2 Br 1.0873 Br 2 (l) + 2 e 1 2 Br 1.066 HBrO + H + + 2 e 1 Br + H 2 O 1.331 HBrO + H + + e 1 1/2 Br 2 (aq) + H 2 O 1.574 HBrO + H + + e 1 1/2 Br 2 (l) + H 2 O 1.596 BrO + H 2 O + 2 e 1 Br + 2 OH 0.761 BrO 3 + 6 H + + 5 e 1 1/2 Br 2 + 3 H 2 O 1.482 BrO 3 + 6 H + + 6 e 1 Br + 3 H 2 O 1.423 BrO 3 + 3 H 2 O + 6 e 1 Br + 6 OH 0.61 (CN) 2 + 2 H + + 2 e 1 2 HCN 0.373 2 HC + 2 H + + 2 e 1 (CN) 2 + 2 H 2 O 0.330 (CNS) 2 + 2 e 1 2 CNS 0.77 CO 2 + 2 H + + 2 e 1 HCOOH 0.199 Ca + + e 1 Ca 3.80 Ca 2+ + 2 e 1 Ca 2.868 Ca(OH) 2 + 2 e 1 Ca + 2 OH 3.02 Calomel electrode, 1 molal KCl 0.2800 Calomel electrode, 1 molar KCl (NCE) 0.2801 Calomel electrode, 0.1 molar KCl 0.3337 Calomel electrode, saturated KCl (SCE) 0.2412 Calomel electrode, saturated NaCl (SSCE) 0.2360 Cd 2+ + 2 e 1 Cd 0.4030 Cd 2+ + 2 e 1 Cd(Hg) 0.3521 Cd(OH) 2 + 2 e 1 Cd(Hg) + 2 OH 0.809 CdSO 4 + 2 e 1 Cd + SO 2 4 0.246 Cd(OH) 2 4 + 2 e 1 Cd + 4 OH 0.658 CdO + H 2 O + 2 e 1 Cd + 2 OH 0.783 Ce 3+ + 3 e 1 Ce 2.336 Ce 3+ + 3 e 1 Ce(Hg) 1.4373 Ce 4+ + e 1 Ce 3+ 1.72 CeOH 3+ + H + + e 1 Ce 3+ + H 2 O 1.715 Cf 4+ + e 1 Cf 3+ 3.3 Cf 3+ + e 1 Cf 2+ 1.6 Cf 3+ + 3 e 1 Cf 1.94 Cf 2+ + 2 e 1 Cf 2.12 Cl 2 (g) + 2 e 1 2 Cl 1.35827 H + H + + e 1 1/2 Cl 2 + H 2 O 1.611 H + H + + 2 e 1 Cl + H 2 O 1.482 + H 2 O + 2 e 1 Cl + 2 OH 0.81 2 + H + + e 1 H 2 1.277 H 2 + 2 H + + 2 e 1 H + H 2 O 1.645 H 2 + 3 H + + 3 e 1 1/2 Cl 2 + 2 H 2 O 1.628 H 2 + 3 H + + 4 e 1 Cl + 2 H 2 O 1.570 2 + H 2 O + 2 e 1 + 2 OH 0.66 2 + 2 H 2 O + 4 e 1 Cl + 4 OH 0.76 2 (aq) + e 1 2 0.954 3 + 2 H + + e 1 2 + H 2 O 1.152 3 + 3 H + + 2 e 1 H 2 + H 2 O 1.214 3 + 6 H + + 5 e 1 1/2 Cl 2 + 3 H 2 O 1.47 3 + 6 H + + 6 e 1 Cl + 3 H 2 O 1.451 3 + H 2 O + 2 e 1 2 + 2 OH 0.33 3 + 3 H 2 O + 6 e 1 Cl + 6 OH 0.62 4 + 2 H + + 2 e 1 3 H 2 O 1.189 4 + 8 H + + 7 e 1 1/2 Cl 2 + 4 H 2 O 1.39 4 + 8 H + + 8 e 1 Cl + 4 H 2 O 1.389 4 + H 2 O + 2 e 1 3 + 2 OH 0.36 Cm 4+ + e 1 Cm 3+ 3.0 Cm 3+ + 3 e 1 Cm 2.04 Co 2+ + 2 e 1 Co 0.28 Co 3+ + e 1 Co 2+ 1.92 [Co(NH 3 ) 6 ] 3+ + e 1 [Co(NH 3 ) 6 ] 2+ 0.108 Co(OH) 2 + 2 e 1 Co + 2 OH 0.73 Co(OH) 3 + e 1 Co(OH) 2 + OH 0.17 Cr 2+ + 2 e 1 Cr 0.913 Cr 3+ + e 1 Cr 2+ 0.407 Cr 3+ + 3 e 1 Cr 0.744 Cr 2 O 2 7 + 14 H + + 6 e 1 2 Cr 3+ + 7 H 2 O 1.232 CrO 2 + 2 H 2 O + 3 e 1 Cr + 4 OH 1.2 HCrO 4 + 7 H + + 3 e 1 Cr 3+ + 4 H 2 O 1.350 CrO 2 + 4 H + + e 1 Cr 3+ + 2H 2 O 1.48 Cr(V) + e 1 Cr(IV) 1.34 CrO 2 4 + 4 H 2 O + 3 e 1 Cr(OH) 3 + 5 OH 0.13 Cr(OH) 3 + 3 e 1 Cr + 3 OH 1.48 Cs + + e 1 Cs 3.026 Cu + + e 1 Cu 0.521 Cu 2+ + e 1 Cu + 0.153 Cu 2+ + 2 e 1 Cu 0.3419 Cu 2+ + 2 e 1 Cu(Hg) 0.345 Cu 3+ + e 1 Cu 2+ 2.4 Cu 2 O 3 + 6 H + + 2e 1 2Cu 2+ + 3 H 2 O 2.0 Cu 2+ + 2 CN + e 1 [Cu(CN) 2 ] 1.103 CuI 2 + e 1 Cu + 2 I 0.00 Cu 2 O + H 2 O + 2 e 1 2 Cu + 2 OH 0.360 Cu(OH) 2 + 2 e 1 Cu + 2 OH 0.222 2 Cu(OH) 2 + 2 e 1 Cu 2 O + 2 OH + H 2 O 0.080 2 D + + 2 e 1 D 2 0.013 Dy 2+ + 2 e 1 Dy 2.2 Dy 3+ + 3 e 1 Dy 2.295 Dy 3+ + e 1 Dy 2+ 2.6 Er 2+ + 2 e 1 Er 2.0 Er 3+ + 3 e 1 Er 2.331 Er 3+ + e 1 Er 2+ 3.0 Es 3+ + e 1 Es 2+ 1.3 Es 3+ + 3 e 1 Es 1.91 Es 2+ + 2 e 1 Es 2.23 Eu 2+ + 2 e 1 Eu 2.812 Eu 3+ + 3 e 1 Eu 1.991

ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) Eu 3+ + e 1 Eu 2+ 0.36 F 2 + 2 H + + 2 e 1 2 HF 3.053 F 2 + 2 e 1 2 F 2.866 F 2 O + 2 H + + 4 e 1 H 2 O + 2 F 2.153 Fe 2+ + 2 e 1 Fe 0.447 Fe 3+ + 3 e 1 Fe 0.037 Fe 3+ + e 1 Fe 2+ 0.771 2 HFeO 4 + 8 H + + 6 e 1 Fe 2 O 3 + 5 H 2 O 2.09 HFeO 4 + 4 H + + 3 e 1 FeOOH + 2 H 2 O 2.08 HFeO 4 + 7 H + + 3 e 1 Fe 3+ + 4 H 2 O 2.07 Fe 2 O 3 + 4 H + + 2 e 1 2 FeOH + + H 2 O 0.16 [Fe(CN) 6 ] 3 + e 1 [Fe(CN) 6 ] 4 0.358 FeO 2 4 + 8 H + + 3 e 1 Fe 3+ + 4 H 2 O 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 H 2 SO 4 ) 1.06 [Ferricinium] + + e 1 ferrocene 0.400 Fm 3+ + e 1 Fm 2+ 1.1 Fm 3+ + 3 e 1 Fm 1.89 Fm 2+ + 2 e 1 Fm 2.30 Fr + + e 1 Fr 2.9 Ga 3+ + 3 e 1 Ga 0.549 Ga + + e 1 Ga 0.2 GaOH 2+ + H + + 3 e 1 Ga + H 2 O 0.498 H 2 GaO 3 + H 2 O + 3 e 1 Ga + 4 OH 1.219 Gd 3+ + 3 e 1 Gd 2.279 Ge 2+ + 2 e 1 Ge 0.24 Ge 4+ + 4 e 1 Ge 0.124 Ge 4+ + 2 e 1 Ge 2+ 0.00 GeO 2 + 2 H + + 2 e 1 GeO + H 2 O 0.118 H 2 GeO 3 + 4 H + + 4 e 1 Ge + 3 H 2 O 0.182 2 H + + 2 e 1 H 2 0.00000 H 2 + 2 e 1 2 H 2.23 HO 2 + H + + e 1 H 2 O 2 1.495 2 H 2 O + 2 e 1 H 2 + 2 OH 0.8277 H 2 O 2 + 2 H + + 2 e 1 2 H 2 O 1.776 Hf 4+ + 4 e 1 Hf 1.55 HfO 2+ + 2 H + + 4 e 1 Hf + H 2 O 1.724 HfO 2 + 4 H + + 4 e 1 Hf + 2 H 2 O 1.505 HfO(OH) 2 + H 2 O + 4 e 1 Hf + 4 OH 2.50 Hg 2+ + 2 e 1 Hg 0.851 2 Hg 2+ + 2 e 1 Hg 2+ 2 0.920 Hg 2+ 2 + 2 e 1 2 Hg 0.7973 Hg 2 (ac) 2 + 2 e 1 2 Hg + 2(ac) 0.51163 Hg 2 Br 2 + 2 e 1 2 Hg + 2 Br 0.13923 Hg 2 Cl 2 + 2 e 1 2 Hg + 2 Cl 0.26808 Hg 2 HPO 4 + 2 e 1 2 Hg + HPO 2 4 0.6359 Hg 2 I 2 + 2 e 1 2 Hg + 2 I 0.0405 Hg 2 O + H 2 O + 2 e 1 2 Hg + 2 OH 0.123 HgO + H 2 O + 2 e 1 Hg + 2 OH 0.0977 Hg(OH) 2 + 2 H + + 2 e 1 Hg + 2 H 2 O 1.034 Hg 2 SO 4 + 2 e 1 2 Hg + SO 2 4 0.6125 Ho 2+ + 2 e 1 Ho 2.1 Ho 3+ + 3 e 1 Ho 2.33 Ho 3+ + e 1 Ho 2+ 2.8 I 2 + 2 e 1 2 I 0.5355 I 3 + 2 e 1 3 I 0.536 H 3 IO 2 6 + 2 e 1 IO 3 + 3 OH 0.7 H 5 IO 6 + H + + 2 e 1 IO 3 + 3 H 2 O 1.601 2 HIO + 2 H + + 2 e 1 I 2 + 2 H 2 O 1.439 HIO + H + + 2 e 1 I + H 2 O 0.987 IO + H 2 O + 2 e 1 I + 2 OH 0.485 2 IO 3 + 12 H + + 10 e 1 I 2 + 6 H 2 O 1.195 IO 3 + 6 H + + 6 e 1 I + 3 H 2 O 1.085 IO 3 + 2 H 2 O + 4 e 1 IO + 4 OH 0.15 IO 3 + 3 H 2 O + 6 e 1 IO + 6 OH 0.26 In + + e 1 In 0.14 In 2+ + e 1 In + 0.40 In 3+ + e 1 In 2+ 0.49 In 3+ + 2 e 1 In + 0.443 In 3+ + 3 e 1 In 0.3382 In(OH) 3 + 3 e 1 In + 3 OH 0.99 In(OH) 4 + 3 e 1 In + 4 OH 1.007 In 2 O 3 + 3 H 2 O + 6 e 1 2 In + 6 OH 1.034 Ir 3+ + 3 e 1 Ir 1.156 [IrCl 6 ] 2 + e 1 [IrCl 6 ] 3 0.8665 [IrCl 6 ] 3 + 3 e 1 Ir + 6 Cl 0.77 Ir 2 O 3 + 3 H 2 O + 6 e 1 2 Ir + 6 OH 0.098 K + + e 1 K 2.931 La 3+ + 3 e 1 La 2.379 La(OH) 3 + 3 e 1 La + 3 OH 2.90 Li + + e 1 Li 3.0401 Lr 3+ + 3 e 1 Lr 1.96 Lu 3+ + 3 e 1 Lu 2.28 Md 3+ + e 1 Md 2+ 0.1 Md 3+ + 3 e 1 Md 1.65 Md 2+ + 2 e 1 Md 2.40 Mg + + e 1 Mg 2.70 Mg 2+ + 2 e 1 Mg 2.372 Mg(OH) 2 + 2 e 1 Mg + 2 OH 2.690 Mn 2+ + 2 e 1 Mn 1.185 Mn 3+ + 3e 1 Mn 2+ 1.5415 MnO 2 + 4 H + + 2 e 1 Mn 2+ + 2 H 2 O 1.224 MnO 4 + e 1 MnO 2 4 0.558 MnO 4 + 4 H + + 3 e 1 MnO 2 + 2 H 2 O 1.679 MnO 4 + 8 H + + 5 e 1 Mn 2+ + 4 H 2 O 1.507 MnO 4 + 2 H 2 O + 3 e 1 MnO 2 + 4 OH 0.595 MnO 2 4 + 2 H 2 O + 2 e 1 MnO 2 + 4 OH 0.60 Mn(OH) 2 + 2 e 1 Mn + 2 OH 1.56 Mn(OH) 3 + e 1 Mn(OH) 2 + OH 0.15 Mn 2 O 3 + 6 H + + e 1 2 Mn 2+ + 3 H 2 O 1.485 Mo 3+ + 3 e 1 Mo 0.200 MoO 2 + 4 H + + 4 e 1 Mo + 4 H 2 O 0.152 H 3 Mo 7 O 3 24 + 45 H + + 42 e 1 7 Mo + 24 H 2 O 0.082 MoO 3 + 6 H + + 6 e 1 Mo + 3 H 2 O 0.075 N 2 + 2 H 2 O + 6 H + + 6 e 1 2 NH 4 OH 0.092 3 N 2 + 2 H + + 2 e 1 2 HN 3 3.09 N + 5 + 3 H + + 2 e 1 2 NH + 4 1.275

ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) N 2 O + 2 H + + 2 e 1 N 2 + H 2 O 1.766 H 2 N 2 O 2 + 2 H + + 2 e 1 N 2 + 2 H 2 O 2.65 N 2 O 4 + 2 e 1 2 2 0.867 N 2 O 4 + 2 H + + 2 e 1 2 NHO 2 1.065 N 2 O 4 + 4 H + + 4 e 1 2 + 2 H 2 O 1.035 2 NH 3 OH + + H + + 2 e 1 N 2 H + 5 + 2 H 2 O 1.42 2 + 2 H + + 2 e 1 N 2 O + H 2 O 1.591 2 + H 2 O + 2 e 1 N 2 O + 2 OH 0.76 H 2 + H + + e 1 + H 2 O 0.983 2 H 2 + 4 H + + 4 e 1 H 2 N 2 O 2 + 2 H 2 O 0.86 2 H 2 + 4 H + + 4 e 1 N 2 O + 3 H 2 O 1.297 2 + H 2 O + e 1 + 2 OH 0.46 2 2 + 2 H 2 O + 4 e 1 N 2 O 2 2 + 4 OH 0.18 2 2 + 3 H 2 O + 4 e 1 N 2 O + 6 OH 0.15 3 + 3 H + + 2 e 1 H 2 + H 2 O 0.934 3 + 4 H + + 3 e 1 + 2 H 2 O 0.957 2 3 + 4 H + + 2 e 1 N 2 O 4 + 2 H 2 O 0.803 3 + H 2 O + 2 e 1 2 + 2 OH 0.01 2 3 + 2 H 2 O + 2 e 1 N 2 O 4 + 4 OH 0.85 Na + + e 1 Na 2.71 Nb 3+ + 3 e 1 Nb 1.099 NbO 2 + 2 H + + 2 e 1 NbO + H 2 O 0.646 NbO 2 + 4 H + + 4 e 1 Nb + 2 H 2 O 0.690 NbO + 2 H + + 2 e 1 Nb + H 2 O 0.733 Nb 2 O 5 + 10 H + + 10 e 1 2 Nb + 5 H 2 O 0.644 Nd 3+ + 3 e 1 Nd 2.323 Nd 2+ + 2 e 1 Nd 2.1 Nd 3+ + e 1 Nd 2+ 2.7 Ni 2+ + 2 e 1 Ni 0.257 Ni(OH) 2 + 2 e 1 Ni + 2 OH 0.72 NiO 2 + 4 H + + 2 e 1 Ni 2+ + 2 H 2 O 1.678 NiO 2 + 2 H 2 O + 2 e 1 Ni(OH) 2 + 2 OH 0.490 No 3+ + e 1 No 2+ 1.4 No 3+ + 3 e 1 No 1.20 No 2+ + 2 e 1 No 2.50 Np 3+ + 3 e 1 Np 1.856 Np 4+ + e 1 Np 3+ 0.147 NpO 2 + H 2 O + H + + e 1 Np(OH) 3 0.962 O 2 + 2 H + + 2 e 1 H 2 O 2 0.695 O 2 + 4 H + + 4 e 1 2 H 2 O 1.229 O 2 + H 2 O + 2 e 1 HO 2 + OH 0.076 O 2 + 2 H 2 O + 2 e 1 H 2 O 2 + 2 OH 0.146 O 2 + 2 H 2 O + 4 e 1 4 OH 0.401 O 3 + 2 H + + 2 e 1 O 2 + H 2 O 2.076 O 3 + H 2 O + 2 e 1 O 2 + 2 OH 1.24 O(g) + 2 H + + 2 e 1 H 2 O 2.421 OH + e 1 OH 2.02 HO 2 + H 2 O + 2 e 1 3 OH 0.878 OsO 4 + 8 H + + 8 e 1 Os + 4 H 2 O 0.838 OsO 4 + 4 H + + 4 e 1 OsO 2 + 2 H 2 O 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 PH 3 (g) 0.111 P(white) + 3 H + + 3 e 1 PH 3 (g) 0.063 P + 3 H 2 O + 3 e 1 PH 3 (g) + 3 OH 0.87 H 2 P 2 + e 1 P + 2 OH 1.82 H 3 PO 2 + H + + e 1 P + 2 H 2 O 0.508 H 3 PO 3 + 2 H + + 2 e 1 H 3 PO 2 + H 2 O 0.499 H 3 PO 3 + 3 H + + 3 e 1 P + 3 H 2 O 0.454 HPO 2 3 + 2 H 2 O + 2 e 1 H 2 PO 2 + 3 OH 1.65 HPO 2 3 + 2 H 2 O + 3 e 1 P + 5 OH 1.71 H 3 PO 4 + 2 H + + 2 e 1 H 3 PO 3 + H 2 O 0.276 PO 3 4 + 2 H 2 O + 2 e 1 HPO 2 3 + 3 OH 1.05 Pa 3+ + 3 e 1 Pa 1.34 Pa 4+ + 4 e 1 Pa 1.49 Pa 4+ + e 1 Pa 3+ 1.9 Pb 2+ + 2 e 1 Pb 0.1262 Pb 2+ + 2 e 1 Pb(Hg) 0.1205 PbBr 2 + 2 e 1 Pb + 2 Br 0.284 PbCl 2 + 2 e 1 Pb + 2 Cl 0.2675 PbF 2 + 2 e 1 Pb + 2 F 0.3444 PbHPO 4 + 2 e 1 Pb + HPO 2 4 0.465 PbI 2 + 2 e 1 Pb + 2 I 0.365 PbO + H 2 O + 2 e 1 Pb + 2 OH 0.580 PbO 2 + 4 H + + 2 e 1 Pb 2+ + 2 H 2 O 1.455 HPbO 2 + H 2 O + 2 e 1 Pb + 3 OH 0.537 PbO 2 + H 2 O + 2 e 1 PbO + 2 OH 0.247 PbO 2 + SO 2 4 + 4 H + + 2 e 1 PbSO 4 + 2 H 2 O 1.6913 PbSO 4 + 2 e 1 Pb + SO 2 4 0.3588 PbSO 4 + 2 e 1 Pb(Hg) + SO 2 4 0.3505 Pd 2+ + 2 e 1 Pd 0.951 [PdCl 4 ] 2 + 2 e 1 Pd + 4 Cl 0.591 [PdCl 6 ] 2 + 2 e 1 [PdCl 4 ] 2 + 2 Cl 1.288 Pd(OH) 2 + 2 e 1 Pd + 2 OH 0.07 Pm 2+ + 2 e 1 Pm 2.2 Pm 3+ + 3 e 1 Pm 2.30 Pm 3+ + e 1 Pm 2+ 2.6 Po 4+ + 2 e 1 Po 2+ 0.9 Po 4+ + 4 e 1 Po 0.76 Pr 4+ + e 1 Pr 3+ 3.2 Pr 2+ + 2 e 1 Pr 2.0 Pr 3+ + 3 e 1 Pr 2.353 Pr 3+ + e 1 Pr 2+ 3.1 Pt 2+ + 2 e 1 Pt 1.18 [PtCl 4 ] 2 + 2 e 1 Pt + 4 Cl 0.755 [PtCl 6 ] 2 + 2 e 1 [PtCl 4 ] 2 + 2 Cl 0.68 Pt(OH) 2 + 2 e 1 Pt + 2 OH 0.14 PtO 3 + 2 H + + 2 e 1 PtO 2 + H 2 O 1.7 PtO 3 + 4 H + + 2 e 1 Pt(OH) 2+ 2 + H 2 O 1.5 PtOH + + H + + 2 e 1 Pt + H 2 O 1.2 PtO 2 + 2 H + + 2 e 1 PtO + H 2 O 1.01 PtO 2 + 4 H + + 4 e 1 Pt + 2 H 2 O 1.00 Pu 3+ + 3 e 1 Pu 2.031 Pu 4+ + e 1 Pu 3+ 1.006 Pu 5+ + e 1 Pu 4+ 1.099 PuO 2 (OH) 2 + 2 H + + 2 e 1 Pu(OH) 4 1.325 PuO 2 (OH) 2 + H + + e 1 PuO 2 OH + H 2 O 1.062 Ra 2+ + 2 e 1 Ra 2.8 Rb + + e 1 Rb 2.98 Re 3+ + 3 e 1 Re 0.300

ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) ReO 4 + 4 H + + 3 e 1 ReO 2 + 2 H 2 O 0.510 ReO 2 + 4 H + + 4 e 1 Re + 2 H 2 O 0.2513 ReO 4 + 2 H + + e 1 ReO 3 + H 2 O 0.768 ReO 4 + 4 H 2 O + 7 e 1 Re + 8 OH 0.584 ReO 4 + 8 H + + 7 e 1 Re + 4 H 2 O 0.368 Rh + + e 1 Rh 0.600 Rh + + 2e1 Rh 0.600 Rh 3+ + 3 e 1 Rh 0.758 [RhCl 6 ] 3 + 3 e 1 Rh + 6 Cl 0.431 RhOH 2+ + H + + 3 e 1 Rh + H 2 O 0.83 Ru 2+ + 2 e 1 Ru 0.455 Ru 3+ + e 1 Ru 2+ 0.2487 RuO 2 + 4 H + + 2 e 1 Ru 2+ + 2 H 2 O 1.120 RuO 4 + e 1 RuO 2 4 0.59 RuO 4 + e 1 RuO 4 1.00 RuO 4 + 6 H + + 4 e 1 Ru(OH) 2+ 2 + 2 H 2 O 1.40 RuO 4 + 8 H + + 8 e 1 Ru + 4 H 2 O 1.038 [Ru(bipy) 3 ) 3+ + e 1 [Ru(bipy) 3 ] 2+ 1.24 [Ru(H 2 O) 6 ] 3+ + e 1 [Ru(H 2 O) 6 ] 2+ 0.23 [Ru(NH 3 ) 6 ] 3+ + e 1 [Ru(NH 3 ) 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 S 2 0.47627 S + 2H + + 2 e 1 H 2 S(aq) 0.142 S + H 2 O + 2 e 1 SH + OH 0.478 2 S + 2 e 1 S 2 2 0.42836 S 2 O 2 6 + 4 H + + 2 e 1 2 H 2 SO 3 0.564 S 2 O 2 8 + 2 e 1 2 SO 2 4 2.010 S 2 O 2 8 + 2 H + + 2 e 1 2 HSO 4 2.123 S 4 O 2 6 + 2 e 1 2 S 2 O 2 3 0.08 2 H 2 SO 3 + H + + 2 e 1 HS 2 O 4 + 2 H 2 O 0.056 H 2 SO 3 + 4 H + + 4 e 1 S + 3 H 2 O 0.449 2 SO 2 3 + 2 H 2 O + 2 e 1 S 2 O 2 4 + 4 OH 1.12 2 SO 2 3 + 3 H 2 O + 4 e 1 S 2 O 2 3 + 6 OH 0.571 SO 2 4 + 4 H + + 2 e 1 H 2 SO 3 + H 2 O 0.172 2 SO 2 4 + 4 H + + 2 e 1 S 2 O 2 6 + H 2 O 0.22 SO 2 4 + H 2 O + 2 e 1 SO 2 3 + 2 OH 0.93 Sb + 3 H + + 3 e 1 SbH 3 0.510 Sb 2 O 3 + 6 H + + 6 e 1 2 Sb + 3 H 2 O 0.152 Sb 2 O 5 (senarmontite) + 4 H + + 4 e 1 Sb 2 O 3 + 2 H 2 O 0.671 Sb 2 O 5 (valentinite) + 4 H + + 4 e 1 Sb 2 O 3 + 2 H 2 O 0.649 Sb 2 O 5 + 6 H + + 4 e 1 2 SbO + + 3 H 2 O 0.581 SbO + + 2 H + + 3 e 1 Sb + 2 H 2 O 0.212 SbO 2 + 2 H 2 O + 3 e 1 Sb + 4 OH 0.66 SbO 3 + H 2 O + 2 e 1 SbO 2 + 2 OH 0.59 Sc 3+ + 3 e 1 Sc 2.077 Se + 2 e 1 Se 2 0.924 Se + 2 H + + 2 e 1 H 2 Se(aq) 0.399 H 2 SeO 3 + 4 H + + 4 e 1 Se + 3 H 2 O 0.74 Se + 2 H + + 2 e 1 H 2 Se 0.082 SeO 2 3 + 3 H 2 O + 4 e 1 Se + 6 OH 0.366 SeO 2 4 + 4 H + + 2 e 1 H 2 SeO 3 + H 2 O 1.151 SeO 2 4 + H 2 O + 2 e 1 SeO 2 3 + 2 OH 0.05 SiF 2 6 + 4 e 1 Si + 6 F 1.24 SiO + 2 H + + 2 e 1 Si + H 2 O 0.8 SiO 2 (quartz) + 4 H + + 4 e 1 Si + 2 H 2 O 0.857 SiO 2 3 + 3 H 2 O + 4 e 1 Si + 6 OH 1.697 Sm 3+ + e 1 Sm 2+ 1.55 Sm 3+ + 3 e 1 Sm 2.304 Sm 2+ + 2 e 1 Sm 2.68 Sn 2+ + 2 e 1 Sn 0.1375 Sn 4+ + 2 e 1 Sn 2+ 0.151 Sn(OH) + 3 + 3 H + + 2 e 1 Sn 2+ + 3 H 2 O 0.142 SnO 2 + 4 H + + 2 e 1 Sn 2+ + 2 H 2 O 0.094 SnO 2 + 4 H + + 4 e 1 Sn + 2 H 2 O 0.117 SnO 2 + 3 H + + 2 e 1 SnOH + + H 2 O 0.194 SnO 2 + 2 H 2 O + 4 e 1 Sn + 4 OH 0.945 HSnO 2 + H 2 O + 2 e 1 Sn + 3 OH 0.909 Sn(OH) 2 6 + 2 e 1 HSnO 2 + 3 OH + H 2 O 0.93 Sr + + e 1 Sr 4.10 Sr 2+ + 2 e 1 Sr 2.899 Sr 2+ + 2 e 1 Sr(Hg) 1.793 Sr(OH) 2 + 2 e 1 Sr + 2 OH 2.88 Ta 2 O 5 + 10 H + + 10 e 1 2 Ta + 5 H 2 O 0.750 Ta 3+ + 3 e 1 Ta 0.6 Tc 2+ + 2 e 1 Tc 0.400 TcO 4 + 4 H + + 3 e 1 TcO 2 + 2 H 2 O 0.782 Tc 3+ + e 1 Tc 2+ 0.3 TcO 4 + 8 H + + 7 e 1 Tc + 4 H 2 O 0.472 Tb 4+ + e 1 Tb 3+ 3.1 Tb 3+ + 3 e 1 Tb 2.28 Te + 2 e 1 Te 2 1.143 Te + 2 H + + 2 e 1 H 2 Te 0.793 Te 4+ + 4 e 1 Te 0.568 TeO 2 + 4 H + + 4 e 1 Te + 2 H 2 O 0.593 TeO 2 3 + 3 H 2 O + 4 e 1 Te + 6 OH 0.57 TeO 4 + 8 H + + 7 e 1 Te + 4 H 2 O 0.472 H 6 TeO 6 + 2 H + + 2 e 1 TeO 2 + 4 H 2 O 1.02 Th 4+ + 4 e 1 Th 1.899 ThO 2 + 4 H + + 4 e 1 Th + 2 H 2 O 1.789 Th(OH) 4 + 4 e 1 Th + 4 OH 2.48 Ti 2+ + 2 e 1 Ti 1.630 Ti 3+ + e 1 Ti 2+ 0.9 TiO 2 + 4 H + + 2 e 1 Ti 2+ + 2 H 2 O 0.502 Ti 3+ + 3 e 1 Ti 1.37 TiOH 3+ + H + + e 1 Ti 3+ + H 2 O 0.055 Tl + + e 1 Tl 0.336 Tl + + e 1 Tl(Hg) 0.3338 Tl 3+ + 2 e 1 Tl + 1.252 Tl 3+ + 3 e 1 Tl 0.741 TlBr + e 1 Tl + Br 0.658 TlCl + e 1 Tl + Cl 0.5568 TlI + e 1 Tl + I 0.752 Tl 2 O 3 + 3 H 2 O + 4 e 1 2 Tl + + 6 OH 0.02 TlOH + e 1 Tl + OH 0.34 Tl(OH) 3 + 2 e 1 TlOH + 2 OH 0.05 Tl 2 SO 4 + 2 e 1 Tl + SO 2 4 0.4360 Tm 3+ + e 1 Tm 2+ 2.2 Tm 3+ + 3 e 1 Tm 2.319 Tm 2+ + 2 e 1 Tm 2.4

ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) U 3+ + 3 e 1 U 1.798 U 4+ + e 1 U 3+ 0.607 UO + 2 + 4 H + + e 1 U 4+ + 2 H 2 O 0.612 UO 2+ 2 + e 1 UO + 2 0.062 UO 2+ 2 + 4 H + + 2 e 1 U 4+ + 2 H 2 O 0.327 UO 2+ 2 + 4 H + + 6 e 1 U + 2 H 2 O 1.444 V 2+ + 2 e 1 V 1.175 V 3+ + e 1 V 2+ 0.255 VO 2+ + 2 H + + e 1 V 3+ + H 2 O 0.337 VO + 2 + 2 H + + e 1 VO 2+ + H 2 O 0.991 V 2 O 5 + 6 H + + 2 e 1 2 VO 2+ + 3 H 2 O 0.957 V 2 O 5 + 10 H + + 10 e 1 2 V + 5 H 2 O 0.242 V(OH) + 4 + 2 H + + e 1 VO 2+ + 3 H 2 O 1.00 V(OH) + 4 + 4 H + + 5 e 1 V + 4 H 2 O 0.254 [V(phen) 3 ] 3+ + e 1 [V(phen) 3 ] 2+ 0.14 W 3+ + 3 e 1 W 0.1 W 2 O 5 + 2 H + + 2 e 1 2 WO 2 + H 2 O 0.031 WO 2 + 4 H + + 4 e 1 W + 2 H 2 O 0.119 WO 3 + 6 H + + 6 e 1 W + 3 H 2 O 0.090 WO 3 + 2 H + + 2 e 1 WO 2 + H 2 O 0.036 2 WO 3 + 2 H + + 2 e 1 W 2 O 5 + H 2 O 0.029 H 4 XeO 6 + 2 H + + 2 e 1 XeO 3 + 3 H 2 O 2.42 XeO 3 + 6 H + + 6 e 1 Xe + 3 H 2 O 2.10 XeF + e 1 Xe + F 3.4 Y 3+ + 3 e 1 Y 2.372 Yb 3+ + e 1 Yb 2+ 1.05 Yb 3+ + 3 e 1 Yb 2.19 Yb 2+ + 2 e 1 Yb 2.76 Zn 2+ + 2 e 1 Zn 0.7618 Zn 2+ + 2 e 1 Zn(Hg) 0.7628 ZnO 2 2 + 2 H 2 O + 2 e 1 Zn + 4 OH 1.215 ZnSO 4 7 H 2 O + 2 e = Zn(Hg) + SO 2 4 + 7 H 2 O 0.7993 (Saturated ZnSO 4 ) ZnOH + + H + + 2 e 1 Zn + H 2 O 0.497 Zn(OH) 2 4 + 2 e 1 Zn + 4 OH 1.199 Zn(OH) 2 + 2 e 1 Zn + 2 OH 1.249 ZnO + H 2 O + 2 e 1 Zn + 2 OH 1.260 ZrO 2 + 4 H + + 4 e 1 Zr + 2 H 2 O 1.553 ZrO(OH) 2 + H 2 O + 4 e 1 Zr + 4 OH 2.36 Zr 4+ + 4 e 1 Zr 1.45 TABLE 2 Reduction s Having E Values More Positive than that of the Standard Hydrogen Electrode 2 H + + 2 e 1 H 2 0.00000 CuI 2 + e 1 Cu + 2 I 0.00 Ge 4+ + 2 e 1 Ge 2+ 0.00 3 + H 2 O + 2 e 1 2 + 2 OH 0.01 Tl 2 O 3 + 3 H 2 O + 4 e 1 2 Tl + + 6 OH 0.02 SeO 2 4 + H 2 O + 2 e 1 SeO 2 3 + 2 OH 0.05 WO 3 + 2 H + + 2 e 1 WO 2 + H 2 O 0.036 UO 2+ 2 + e = UO + 2 0.062 Pd(OH) 2 + 2 e 1 Pd + 2 OH 0.07 AgBr + e 1 Ag + Br 0.07133 MoO 3 + 6 H + + 6 e 1 Mo + 3 H 2 O 0.075 S 4 O 2 6 + 2 e 1 2 S 2 O 2 3 0.08 H 3 Mo 7 O 3 24 + 45 H + + 42 e 1 7 Mo + 24 H 2 O 0.082 AgSCN + e 1 Ag + SCN 0.8951 N 2 + 2 H 2 O + 6 H + + 6 e 1 2 NH 4 OH 0.092 HgO + H 2 O + 2 e 1 Hg + 2 OH 0.0977 Ir 2 O 3 + 3 H 2 O + 6 e 1 2 Ir + 6 OH 0.098 2 + 2 e 1 N 2 O 2 2 0.10 [Ru(NH 3 ) 6 ] 3+ + e 1 [Ru(NH 3 ) 6 ] 2+ 0.10 W 3+ + 3 e 1 W 0.1 [Co(NH 3 ) 6 ] 3+ + e 1 [Co(NH 3 ) 6 ] 2+ 0.108 Hg 2 O + H 2 O + 2 e 1 2 Hg + 2 OH 0.123 Ge 4+ + 4 e 1 Ge 0.124 Hg 2 Br 2 + 2 e 1 2 Hg + 2 Br 0.13923 Pt(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 H 2 S(aq) 0.142 Sn(OH) + 3 + 3 H + + 2 e 1 Sn 2+ + 3 H 2 O 0.142 Np 4+ + e 1 Np 3+ 0.147 Ag 4 [Fe(CN) 6 ] + 4 e 1 4 Ag + [Fe(CN) 6 ] 4 0.1478 IO 3 + 2 H 2 O + 4 e 1 IO + 4 OH 0.15 Mn(OH) 3 + e 1 Mn(OH) 2 + OH 0.15 2 2 + 3 H 2 O + 4 e 1 N 2 O + 6 OH 0.15 Sn 4+ + 2 e 1 Sn 2+ 0.151 Sb 2 O 3 + 6 H + + 6 e 1 2 Sb + 3 H 2 O 0.152 Cu 2+ + e 1 Cu + 0.153 BiOCl + 2 H + + 3 e 1 Bi + Cl + H 2 O 0.1583 BiCl 4 + 3 e 1 Bi + 4 Cl 0.16 Fe 2 O 3 + 4 H + + 2 e 1 2 FeOH + + H 2 O 0.16 Co(OH) 3 + e 1 Co(OH) 2 + OH 0.17 SO 2 4 + 4 H + + 2 e 1 H 2 SO 3 + H 2 O 0.172 Bi 3+ + 2 e 1 Bi + 0.2 [Ru(en) 3 ] 3+ + e 1 [Ru(en) 3 ] 2+ 0.210 SbO + + 2 H + + 3 e 1 Sb + 2 H 2 O 0.212 AgCl + e 1 Ag + Cl 0.22233 [Ru(H 2 O) 6 ] 3+ + e 1 [Ru(H 2 O) 6 ] 2+ 0.23 As 2 O 3 + 6 H + + 6 e 1 2 As + 3 H 2 O 0.234 Calomel electrode, saturated NaCl (SSCE) 0.2360 Ge 2+ + 2 e 1 Ge 0.24 Ru 3+ + e 1 Ru 2+ 0.24 Calomel electrode, saturated KCl 0.2412 PbO 2 + H 2 O + 2 e 1 PbO + 2 OH 0.247 HAsO 2 + 3 H + + 3 e 1 As + 2 H 2 O 0.248 Ru 3+ + e 1 Ru 2+ 0.2487

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 cm 2 mol -1 (i.e., Ω -1 cm 2 mol -1 ). The first part of this table gives the molar conductivity of the hydrohalogen acids at 25 C as a function of the concentration in mol/l. The second part gives the temperature dependence of Λ for HCl and HBr. More extensive tables and mathematical representations 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. 405.1 426.1 427.7 426.4 0.0001 424.5 425.9 424.6 0.0005 422.6 424.3 423.0 0.001 421.2 422.9 421.7 0.005 128.1 415.7 417.6 416.4 0.01 96.1 411.9 413.7 412.8 0.05 50.1 398.9 400.4 400.8 0.10 39.1 391.1 391.9 394.0 0.5 26.3 360.7 361.9 369.8 1.0 24.3 332.2 334.5 343.9 1.5 305.8 307.6 316.4 2.0 281.4 281.7 288.9 2.5 258.9 257.8 262.5 3.0 237.6 236.8 237.9 c/mol L 1 HF HCl HBr HI 3.5 218.3 217.5 215.4 4.0 200.0 199.4 195.1 4.5 183.1 182.4 176.8 5.0 167.4 166.5 160.4 5.5 152.9 151.8 145.5 6.0 139.7 138.2 131.7 6.5 127.7 125.7 118.6 7.0 116.9 114.2 105.7 7.5 107.0 103.8 8.0 98.2 94.4 8.5 90.3 85.8 9.0 83.1 9.5 76.6 10.0 70.7 c/mol L 1 20 C 10 C 0 C 10 C 20 C 30 C 40 C 50 C HCl 0.5 228.7 283.0 336.4 386.8 436.9 482.4 1.0 211.7 261.6 312.2 359.0 402.9 445.3 1.5 196.2 241.5 287.5 331.1 371.6 410.8 2.0 182.0 222.7 262.9 303.3 342.4 378.2 2.5 131.7 168.5 205.1 239.8 277.0 315.2 347.6 3.0 120.8 154.6 188.5 219.3 253.3 289.3 319.0 3.5 85.5 111.3 139.6 172.2 201.6 232.9 263.9 292.1 4.0 79.3 102.7 129.2 158.1 185.6 214.2 242.2 268.2 4.5 73.7 94.9 119.5 145.4 170.6 196.6 222.5 246.7 5.0 68.5 87.8 110.3 133.5 156.6 180.2 204.1 226.5 5.5 63.6 81.1 101.7 122.5 143.6 165.0 187.1 207.7 6.0 58.9 74.9 93.7 112.3 131.5 151.0 171.3 190.3 6.5 54.4 69.1 86.2 103.0 120.4 138.2 156.9 174.3 7.0 50.2 63.7 79.3 94.4 110.2 126.4 143.3 159.7 7.5 46.3 58.6 73.0 86.5 100.9 115.7 131.6 146.2 8.0 42.7 54.0 67.1 79.4 92.4 106.1 120.6 134.0 8.5 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 89.4 101.7 112.9 9.5 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 88.4 11.0 26.8 33.4 41.1 48.8 56.1 64.9 73.6 81.7 11.5 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 70.0 12.5 21.4 26.7 32.7 39.0 44.4 51.4 57.9 64.8 5-90

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 0.5 240.9 295.9 347.0 398.9 453.6 496.8 1.0 229.6 276.0 329.0 380.4 418.6 465.2 1.5 209.5 254.9 298.9 340.6 381.8 421.4 2.0 150.8 188.6 231.3 271.8 314.1 350.5 387.4 2.5 136.8 171.7 208.3 244.8 281.7 316.0 349.1 3.0 125.7 157.2 189.5 222.2 255.0 287.8 318.6 3.5 116.1 144.1 174.6 203.2 234.4 263.7 291.9 4.0 84.0 107.5 132.3 160.2 186.8 214.2 239.7 266.9 4.5 78.0 99.0 123.0 146.4 171.2 195.1 218.8 242.6 5.0 72.3 91.4 112.6 134.0 155.7 178.2 199.6 221.3 5.5 67.0 84.2 103.1 122.7 142.1 162.8 181.4 201.8 6.0 61.8 77.2 94.3 112.0 129.6 148.0 165.4 183.4 6.5 56.8 70.7 86.0 102.0 118.0 134.1 150.5 166.3 7.0 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 CO 2 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. 10 4 k/s m -1 t/ C 0.01 m KCl 0.1 m KCl 1.0 m KCl H 2 O (CO 2 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 5-91

EQUIVALENT CONDUCTIVITY OF ELECTROLYTES IN AQUEOUS SOLUTION Petr Vanýsek 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 m 2 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 )c 1/2 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, Ionic Conductivity and Diffusion at Infinite Dilution. The equation is reliable for c < 0.001 mol/l; with higher concentration the error increases. Concentration (mol/l) Infinite Compound dilution 0.0005 0.001 0.005 0.01 0.02 0.05 0.1 Λ Λ Ag 3 133.29 131.29 130.45 127.14 124.70 121.35 115.18 109.09 1/2BaCl 2 139.91 135.89 134.27 127.96 123.88 119.03 111.42 105.14 1/2CaCl 2 135.77 131.86 130.30 124.19 120.30 115.59 108.42 102.41 1/2Ca(OH) 2 258 233 226 214 1/2CuSO 4 133.6 121.6 115.20 94.02 83.08 72.16 59.02 50.55 HCl 425.95 422.53 421.15 415.59 411.80 407.04 398.89 391.13 KBr 151.9 149.8 148.9 146.02 143.36 140.41 135.61 131.32 KCl 149.79 147.74 146.88 143.48 141.20 138.27 133.30 128.90 K 4 139.97 138.69 137.80 134.09 131.39 127.86 121.56 115.14 1/3K 3 Fe(CN) 6 174.5 166.4 163.1 150.7 1/4K 4 Fe(CN) 6 184 167.16 146.02 134.76 122.76 107.65 97.82 KHCO 3 117.94 116.04 115.28 112.18 110.03 107.17 KI 150.31 148.2 143.32 144.30 142.11 139.38 134.90 131.05 KIO 4 127.86 125.74 124.88 121.18 118.45 114.08 106.67 98.2 K 3 144.89 142.70 141.77 138.41 132.75 132.34 126.25 120.34 KMnO 4 134.8 132.7 131.9 126.5 113 KOH 271.5 234 230 228 219 213 KReO 4 128.20 126.03 125.12 121.31 118.49 114.49 106.40 97.40 1/3LaCl 3 145.9 139.6 137.0 127.5 121.8 115.3 106.2 99.1 LiCl 114.97 113.09 112.34 109.35 107.27 104.60 100.06 95.81 Li 4 105.93 104.13 103.39 100.52 98.56 96.13 92.15 88.52 1/2MgCl 2 129.34 125.55 124.15 118.25 114.49 109.99 103.03 97.05 NH 4 Cl 149.6 147.5 146.7 134.4 141.21 138.25 133.22 128.69 NaCl 126.39 124.44 123.68 120.59 118.45 115.70 111.01 106.69 Na 4 117.42 115.58 114.82 111.70 109.54 106.91 102.35 98.38 NaI 126.88 125.30 124.19 121.19 119.18 116.64 112.73 108.73 NaOOCCH 3 91.0 89.2 88.5 85.68 83.72 81.20 76.88 72.76 NaOH 247.7 245.5 244.6 240.7 237.9 Na picrate 80.45 78.7 78.6 75.7 73.7 66.3 61.8 1/2Na 2 SO 4 129.8 125.68 124.09 117.09 112.38 106.73 97.70 89.94 1/2SrCl 2 135.73 131.84 130.27 124.18 120.23 115.48 108.20 102.14 1/2ZnSO 4 132.7 121.3 114.47 95.44 84.87 74.20 61.17 52.61 5-92

IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION Petr Vanýsek 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 2 D RT / F λ / z = ( )( ) 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, D salt, may be calculated from the D + and D values of the constituent ions by the relation ( ) z+ + z D+ D Dsalt = z+ D+ + z D 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 Λ = λ + + λ 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 D Ion 10-4 m 2 S mol -1 10-5 cm 2 s -1 Inorganic Cations Ag + 61.9 1.648 1/3Al 3+ 61 0.541 1/2Ba 2+ 63.6 0.847 1/2Be 2+ 45 0.599 1/2Ca 2+ 59.47 0.792 1/2Cd 2+ 54 0.719 1/3Ce 3+ 69.8 0.620 1/2Co 2+ 55 0.732 1/3[Co(NH 3 ) 6 ] 3+ 101.9 0.904 1/3[Co(en) 3 ] 3+ 74.7 0.663 1/6[Co 2 (trien) 3 ] 6+ 69 0.306 1/3Cr 3+ 67 0.595 Cs + 77.2 2.056 1/2Cu 2+ 53.6 0.714 D + 249.9 6.655 1/3Dy 3+ 65.6 0.582 1/3Er 3+ 65.9 0.585 1/3Eu 3+ 67.8 0.602 1/2Fe 2+ 54 0.719 1/3Fe 3+ 68 0.604 1/3Gd 3+ 67.3 0.597 H + 349.65 9.311 1/2Hg 2+ 68.6 0.913 1/2Hg 2+ 63.6 0.847 λ D Ion 10-4 m 2 S mol -1 10-5 cm 2 s -1 1/3Ho 3+ 66.3 0.589 K + 73.48 1.957 1/3La 3+ 69.7 0.619 Li + 38.66 1.029 1/2Mg 2+ 53.0 0.706 1/2Mn 2+ 53.5 0.712 NH + 4 73.5 1.957 N 2 H + 5 59 1.571 Na + 50.08 1.334 1/3Nd 3+ 69.4 0.616 1/2Ni 2+ 49.6 0.661 1/4[Ni 2 (trien) 3 ] 4+ 52 0.346 1/2Pb 2+ 71 0.945 1/3Pr 3+ 69.5 0.617 1/2Ra 2+ 66.8 0.889 Rb + 77.8 2.072 1/3Sc 3+ 64.7 0.574 1/3Sm 3+ 68.5 0.608 1/2Sr 2+ 59.4 0.791 Tl + 74.7 1.989 1/3Tm 3+ 65.4 0.581 1/2UO 2+ 2 32 0.426 1/3Y 3+ 62 0.550 1/3Yb 3+ 65.6 0.582 1/2Zn 2+ 52.8 0.703

IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION (continued) λ D λ D Ion 10-4 m 2 S mol -1 10-5 cm 2 s -1 Ion 10-4 m 2 S mol -1 10-5 cm 2 s -1 Inorganic Anions Au(CN) - 2 50 1.331 Au(CN) - 4 36 0.959 B(C 6 H 5 ) - 4 21 0.559 Br - 78.1 2.080 Br - 3 43 1.145 BrO - 3 55.7 1.483 CN - 78 2.077 C - 64.6 1.720 1/2CO 2-3 69.3 0.923 Cl - 76.31 2.032-2 52 1.385-3 64.6 1.720-4 67.3 1.792 1/3[Co(CN) 6 ] 3-98.9 0.878 1/2CrO 2-4 85 1.132 F - 55.4 1.475 1/4[Fe(CN) 6 ] 4-110.4 0.735 1/3[Fe(CN) 6 ] 3-100.9 0.896 H 2 AsO - 4 34 0.905 HCO - 3 44.5 1.185 HF - 2 75 1.997 1/2HPO 2-4 57 0.759 H 2 PO - 4 36 0.959 H 2 PO - 2 46 1.225 HS - 65 1.731 HSO - 3 58 1.545 HSO - 4 52 1.385 H 2 SbO - 4 31 0.825 I - 76.8 2.045 IO - 3 40.5 1.078 IO - 4 54.5 1.451 MnO - 4 61.3 1.632 1/2MoO 2-4 74.5 1.984 N(CN) - 2 54.5 1.451-2 71.8 1.912-3 71.42 1.902 NH 2 SO - 3 48.3 1.286 N - 3 69 1.837 OCN - 64.6 1.720 OD - 119 3.169 OH - 198 5.273 PF - 6 56.9 1.515 1/2PO 3 F 2-63.3 0.843 1/3PO 3-4 92.8 0.824 1/4P 2 O 4-7 96 0.639 1/3P 3 O 3-9 83.6 0.742 1/5P 3 O 5-10 109 0.581 ReO - 4 54.9 1.462 SCN - 66 1.758 1/2SO 2-3 72 0.959 1/2SO 2-4 80.0 1.065 1/2S 2 O 2-3 85.0 1.132 1/2S 2 O 2-4 66.5 0.885 1/2S 2 O 2-6 93 1.238 1/2S 2 O 2-8 86 1.145 Sb(OH) - 6 31.9 0.849 SeCN - 64.7 1.723 1/2SeO 2-4 75.7 1.008 1/2WO 2-4 69 0.919 Organic Cations Benzyltrimethylammonium + 34.6 0.921 Isobutylammonium + 38 1.012 Butyltrimethylammonium + 33.6 0.895 Decylpyridinium + 29.5 0.786 Decyltrimethylammonium + 24.4 0.650 Diethylammonium + 42.0 1.118 Dimethylammonium + 51.8 1.379 Dipropylammonium + 30.1 0.802 Dodecylammonium + 23.8 0.634 Dodecyltrimethylammonium + 22.6 0.602 Ethanolammonium + 42.2 1.124 Ethylammonium + 47.2 1.257 Ethyltrimethylammonium + 40.5 1.078 Hexadecyltrimethylammonium + 20.9 0.557 Hexyltrimethylammonium + 29.6 0.788 Histidyl + 23.0 0.612 Hydroxyethyltrimethylarsonium + 39.4 1.049 Methylammonium + 58.7 1.563 Octadecylpyridinium + 20 0.533 Octadecyltributylammonium + 16.6 0.442 Octadecyltriethylammonium + 17.9 0.477 Octadecyltrimethylammonium + 19.9 0.530 Octadecyltripropylammonium + 17.2 0.458 Octyltrimethylammonium + 26.5 0.706 Pentylammonium + 37 0.985 Piperidinium + 37.2 0.991 Propylammonium + 40.8 1.086 Pyrilammonium + 24.3 0.647 Tetrabutylammonium + 19.5 0.519 Tetradecyltrimethylammonium + 21.5 0.573 Tetraethylammonium + 32.6 0.868 Tetramethylammonium + 44.9 1.196 Tetraisopentylammonium + 17.9 0.477 Tetrapentylammmonium + 17.5 0.466 Tetrapropylammonium + 23.4 0.623 Triethylammonium + 34.3 0.913 Triethylsulfonium + 36.1 0.961 Trimethylammonium + 47.23 1.258 Trimethylhexylammonium + 34.6 0.921 Trimethylsulfonium + 51.4 1.369 Tripropylammonium + 26.1 0.695 Organic Anions Acetate - 40.9 1.089 p-anisate - 29.0 0.772 1/2Azelate 2-40.6 0.541 Benzoate - 32.4 0.863 Bromoacetate - 39.2 1.044 Bromobenzoate - 30 0.799 Butyrate - 32.6 0.868 Chloroacetate - 39.8 1.060 m-chlorobenzoate - 31 0.825 o-chlorobenzoate - 30.2 0.804

IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION (continued) λ D λ D Ion 10-4 m 2 S mol -1 10-5 cm 2 s -1 Ion 10-4 m 2 S mol -1 10-5 cm 2 s -1 1/3Citrate 3-70.2 0.623 Crotonate - 33.2 0.884 Cyanoacetate - 43.4 1.156 Cyclohexane carboxylate - 28.7 0.764 1/2 1,1-Cyclopropanedicarboxylate 2-53.4 0.711 Decylsulfate - 26 0.692 Dichloroacetate - 38.3 1.020 1/2Diethylbarbiturate 2-26.3 0.350 Dihydrogencitrate - 30 0.799 1/2Dimethylmalonate 2-49.4 0.658 3,5-Dinitrobenzoate - 28.3 0.754 Dodecylsulfate - 24 0.639 Ethylmalonate - 49.3 1.313 Ethylsulfate - 39.6 1.055 Fluoroacetate - 44.4 1.182 Fluorobenzoate - 33 0.879 Formate - 54.6 1.454 1/2Fumarate 2-61.8 0.823 1/2Glutarate 2-52.6 0.700 Hydrogenoxalate - 40.2 1.070 Isovalerate - 32.7 0.871 Iodoacetate - 40.6 1.081 Lactate - 38.8 1.033 1/2Malate 2-58.8 0.783 1/2Maleate 2-61.9 0.824 1/2Malonate 2-63.5 0.845 Methylsulfate - 48.8 1.299 Naphthylacetate - 28.4 0.756 1/2Oxalate 2-74.11 0.987 Octylsulfate - 29 0.772 Phenylacetate - 30.6 0.815 1/2o-Phthalate 2-52.3 0.696 1/2m-Phthalate 2-54.7 0.728 Picrate - 30.37 0.809 Pivalate - 31.9 0.849 Propionate - 35.8 0.953 Propylsulfate - 37.1 0.988 Salicylate - 36 0.959 1/2Suberate 2-36 0.479 1/2Succinate 2-58.8 0.783 p-sulfonate 29.3 0.780 1/2Tartarate 2-59.6 0.794 Trichloroacetate - 35 0.932