ELECTROCHEMICAL SERIES. Petr Vanýsek

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1 ELECTROCHEMICAL SERIES Petr Vanýsek There are three tables for this electrochemical series. Each table lists standard reduction potentials, E values, at K (25 C), and at a pressure of 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 V to 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 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, A. J. Bard, R. Parsons, and J. Jordan, Standard Potentials in Aqueous Solutions, Marcel Dekker, New York, S. G. Bratsch, J. Phys. Chem. Ref. Data, 18, 1 21, TABLE 1 Alphabetical Listing Ac e 1 Ac 2.20 Ag + + e 1 Ag Ag 2+ + e 1 Ag Ag(ac) + e 1 Ag + (ac) AgBr + e 1 Ag + Br AgBrO 3 + e 1 Ag + BrO Ag 2 C 2 O e 1 2 Ag + C 2 O AgCl + e 1 Ag + Cl AgCN + e 1 Ag + CN Ag 2 CO e 1 2 Ag + CO Ag 2 CrO e 1 2 Ag + CrO AgF + e 1 Ag + F Ag 4 [Fe(CN) 6 ] + 4 e 1 4 Ag + [Fe(CN) 6 ] AgI + e 1 Ag + I AgIO 3 + e 1 Ag + IO Ag 2 MoO e 1 2 Ag + MoO Ag 2 + e 1 Ag Ag 2 O + H 2 O + 2 e 1 2 Ag + 2 OH Ag 2 O 3 + H 2 O + 2 e 1 2 AgO + 2 OH Ag e 1 Ag Ag 3+ + e 1 Ag Ag 2 O H + + e 1 2 Ag + 2 H 2 O AgO + H 2 O + 2 e 1 Ag 2 O + 2 OH AgOCN + e 1 Ag + OCN 0.41 Ag 2 S + 2 e 1 2 Ag + S Ag 2 S + 2 H e 1 2 Ag + H 2 S AgSCN + e 1 Ag + SCN Ag 2 SeO e 1 2 Ag + SeO Ag 2 SO e 1 2 Ag + SO Ag 2 WO e 1 2 Ag + WO Al e 1 Al Al(OH) e 1 Al + 3 OH 2.31 Al(OH) e 1 Al + 4 OH H 2 AlO 3 + H 2 O + 3 e 1 Al + 4 OH 2.33 AlF e 1 Al + 6 F Am 4+ + e 1 Am Am e 1 Am 1.9 Am e 1 Am Am 3+ + e 1 Am As + 3 H e 1 AsH As 2 O H e 1 2 As + 3 H 2 O HAsO H e 1 As + 2 H 2 O AsO H 2 O + 3 e 1 As + 4 OH 0.68 H 3 AsO H e 1 HAsO H 2 O AsO H 2 O + 2 e 1 AsO OH 0.71 At e 1 2 At 0.3 Au + + e 1 Au Au e 1 Au Au e 1 Au Au 2+ + e 1 Au AuOH 2+ + H e 1 Au + + H 2 O 1.32 AuBr 2 + e 1 Au + 2 Br AuBr e 1 Au + 4 Br AuCl e 1 Au + 4 Cl Au(OH) H e 1 Au + 3 H 2 O 1.45 H 2 BO H 2 O + 8 e 1 BH OH 1.24 H 2 BO 3 + H 2 O + 3 e 1 B + 4 OH 1.79 H 3 BO H e 1 B + 3 H 2 O B(OH) H e 1 BH H 2 O Ba e 1 Ba Ba e 1 Ba(Hg) Ba(OH) e 1 Ba + 2 OH 2.99 Be e 1 Be Be 2 O H 2 O + 4 e 1 2 Be + 6 OH 2.63

2 ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) p benzoquinone + 2 H e 1 hydroquinone Bi + + e 1 Bi 0.5 Bi e 1 Bi Bi e 1 Bi Bi + 3 H e 1 BiH BiCl e 1 Bi + 4 Cl 0.16 Bi 2 O H 2 O + 6 e 1 2 Bi + 6 OH 0.46 Bi 2 O H e 1 2 BiO H 2 O BiO H e 1 Bi + H 2 O BiOCl + 2 H e 1 Bi + Cl + H 2 O Bk 4+ + e 1 Bk Bk e 1 Bk 1.6 Bk 3+ + e 1 Bk Br 2 (aq) + 2 e 1 2 Br Br 2 (l) + 2 e 1 2 Br HBrO + H e 1 Br + H 2 O HBrO + H + + e 1 1/2 Br 2 (aq) + H 2 O HBrO + H + + e 1 1/2 Br 2 (l) + H 2 O BrO + H 2 O + 2 e 1 Br + 2 OH BrO H e 1 1/2 Br H 2 O BrO H e 1 Br + 3 H 2 O BrO H 2 O + 6 e 1 Br + 6 OH 0.61 (CN) H e 1 2 HCN HC + 2 H e 1 (CN) H 2 O (CNS) e 1 2 CNS 0.77 CO H e 1 HCOOH Ca + + e 1 Ca 3.80 Ca e 1 Ca Ca(OH) e 1 Ca + 2 OH 3.02 Calomel electrode, 1 molal KCl Calomel electrode, 1 molar KCl (NCE) Calomel electrode, 0.1 molar KCl Calomel electrode, saturated KCl (SCE) Calomel electrode, saturated NaCl (SSCE) Cd e 1 Cd Cd e 1 Cd(Hg) Cd(OH) e 1 Cd(Hg) + 2 OH CdSO e 1 Cd + SO Cd(OH) e 1 Cd + 4 OH CdO + H 2 O + 2 e 1 Cd + 2 OH Ce e 1 Ce Ce e 1 Ce(Hg) Ce 4+ + e 1 Ce CeOH 3+ + H + + e 1 Ce 3+ + H 2 O Cf 4+ + e 1 Cf Cf 3+ + e 1 Cf Cf e 1 Cf 1.94 Cf e 1 Cf 2.12 Cl 2 (g) + 2 e 1 2 Cl H + H + + e 1 1/2 Cl 2 + H 2 O H + H e 1 Cl + H 2 O H 2 O + 2 e 1 Cl + 2 OH H + + e 1 H H H e 1 H + H 2 O H H e 1 1/2 Cl H 2 O H H e 1 Cl + 2 H 2 O H 2 O + 2 e OH H 2 O + 4 e 1 Cl + 4 OH (aq) + e H + + e H 2 O H e 1 H 2 + H 2 O H e 1 1/2 Cl H 2 O H e 1 Cl + 3 H 2 O H 2 O + 2 e OH H 2 O + 6 e 1 Cl + 6 OH H e 1 3 H 2 O H e 1 1/2 Cl H 2 O H e 1 Cl + 4 H 2 O H 2 O + 2 e OH 0.36 Cm 4+ + e 1 Cm Cm e 1 Cm 2.04 Co e 1 Co 0.28 Co 3+ + e 1 Co [Co(NH 3 ) 6 ] 3+ + e 1 [Co(NH 3 ) 6 ] Co(OH) e 1 Co + 2 OH 0.73 Co(OH) 3 + e 1 Co(OH) 2 + OH 0.17 Cr e 1 Cr Cr 3+ + e 1 Cr Cr e 1 Cr Cr 2 O H e 1 2 Cr H 2 O CrO H 2 O + 3 e 1 Cr + 4 OH 1.2 HCrO H e 1 Cr H 2 O CrO H + + e 1 Cr H 2 O 1.48 Cr(V) + e 1 Cr(IV) 1.34 CrO H 2 O + 3 e 1 Cr(OH) OH 0.13 Cr(OH) e 1 Cr + 3 OH 1.48 Cs + + e 1 Cs Cu + + e 1 Cu Cu 2+ + e 1 Cu Cu e 1 Cu Cu e 1 Cu(Hg) Cu 3+ + e 1 Cu Cu 2 O H + + 2e 1 2Cu H 2 O 2.0 Cu CN + e 1 [Cu(CN) 2 ] CuI 2 + e 1 Cu + 2 I 0.00 Cu 2 O + H 2 O + 2 e 1 2 Cu + 2 OH Cu(OH) e 1 Cu + 2 OH Cu(OH) e 1 Cu 2 O + 2 OH + H 2 O D e 1 D Dy e 1 Dy 2.2 Dy e 1 Dy Dy 3+ + e 1 Dy Er e 1 Er 2.0 Er e 1 Er Er 3+ + e 1 Er Es 3+ + e 1 Es Es e 1 Es 1.91 Es e 1 Es 2.23 Eu e 1 Eu Eu e 1 Eu 1.991

3 ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) Eu 3+ + e 1 Eu F H e 1 2 HF F e 1 2 F F 2 O + 2 H e 1 H 2 O + 2 F Fe e 1 Fe Fe e 1 Fe Fe 3+ + e 1 Fe HFeO H e 1 Fe 2 O H 2 O 2.09 HFeO H e 1 FeOOH + 2 H 2 O 2.08 HFeO H e 1 Fe H 2 O 2.07 Fe 2 O H e 1 2 FeOH + + H 2 O 0.16 [Fe(CN) 6 ] 3 + e 1 [Fe(CN) 6 ] FeO H e 1 Fe H 2 O 2.20 [Fe(bipy) 2 ] 3+ + e 1 Fe(bipy) 2 ] [Fe(bipy) 3 ] 3+ + e 1 Fe(bipy) 3 ] Fe(OH) 3 + e 1 Fe(OH) 2 + OH 0.56 [Fe(phen) 3 ] 3+ + e 1 [Fe(phen) 3 ] [Fe(phen) 3 ] 3+ + e 1 [Fe(phen) 3 ] 2+ (1 molar H 2 SO 4 ) 1.06 [Ferricinium] + + e 1 ferrocene Fm 3+ + e 1 Fm Fm e 1 Fm 1.89 Fm e 1 Fm 2.30 Fr + + e 1 Fr 2.9 Ga e 1 Ga Ga + + e 1 Ga 0.2 GaOH 2+ + H e 1 Ga + H 2 O H 2 GaO 3 + H 2 O + 3 e 1 Ga + 4 OH Gd e 1 Gd Ge e 1 Ge 0.24 Ge e 1 Ge Ge e 1 Ge GeO H e 1 GeO + H 2 O H 2 GeO H e 1 Ge + 3 H 2 O H e 1 H H e 1 2 H 2.23 HO 2 + H + + e 1 H 2 O H 2 O + 2 e 1 H OH H 2 O H e 1 2 H 2 O Hf e 1 Hf 1.55 HfO H e 1 Hf + H 2 O HfO H e 1 Hf + 2 H 2 O HfO(OH) 2 + H 2 O + 4 e 1 Hf + 4 OH 2.50 Hg e 1 Hg Hg e 1 Hg Hg e 1 2 Hg Hg 2 (ac) e 1 2 Hg + 2(ac) Hg 2 Br e 1 2 Hg + 2 Br Hg 2 Cl e 1 2 Hg + 2 Cl Hg 2 HPO e 1 2 Hg + HPO Hg 2 I e 1 2 Hg + 2 I Hg 2 O + H 2 O + 2 e 1 2 Hg + 2 OH HgO + H 2 O + 2 e 1 Hg + 2 OH Hg(OH) H e 1 Hg + 2 H 2 O Hg 2 SO e 1 2 Hg + SO Ho e 1 Ho 2.1 Ho e 1 Ho 2.33 Ho 3+ + e 1 Ho I e 1 2 I I e 1 3 I H 3 IO e 1 IO OH 0.7 H 5 IO 6 + H e 1 IO H 2 O HIO + 2 H e 1 I H 2 O HIO + H e 1 I + H 2 O IO + H 2 O + 2 e 1 I + 2 OH IO H e 1 I H 2 O IO H e 1 I + 3 H 2 O IO H 2 O + 4 e 1 IO + 4 OH 0.15 IO H 2 O + 6 e 1 IO + 6 OH 0.26 In + + e 1 In 0.14 In 2+ + e 1 In In 3+ + e 1 In In e 1 In In e 1 In In(OH) e 1 In + 3 OH 0.99 In(OH) e 1 In + 4 OH In 2 O H 2 O + 6 e 1 2 In + 6 OH Ir e 1 Ir [IrCl 6 ] 2 + e 1 [IrCl 6 ] [IrCl 6 ] e 1 Ir + 6 Cl 0.77 Ir 2 O H 2 O + 6 e 1 2 Ir + 6 OH K + + e 1 K La e 1 La La(OH) e 1 La + 3 OH 2.90 Li + + e 1 Li Lr e 1 Lr 1.96 Lu e 1 Lu 2.28 Md 3+ + e 1 Md Md e 1 Md 1.65 Md e 1 Md 2.40 Mg + + e 1 Mg 2.70 Mg e 1 Mg Mg(OH) e 1 Mg + 2 OH Mn e 1 Mn Mn e 1 Mn MnO H e 1 Mn H 2 O MnO 4 + e 1 MnO MnO H e 1 MnO H 2 O MnO H e 1 Mn H 2 O MnO H 2 O + 3 e 1 MnO OH MnO H 2 O + 2 e 1 MnO OH 0.60 Mn(OH) e 1 Mn + 2 OH 1.56 Mn(OH) 3 + e 1 Mn(OH) 2 + OH 0.15 Mn 2 O H + + e 1 2 Mn H 2 O Mo e 1 Mo MoO H e 1 Mo + 4 H 2 O H 3 Mo 7 O H e 1 7 Mo + 24 H 2 O MoO H e 1 Mo + 3 H 2 O N H 2 O + 6 H e 1 2 NH 4 OH N H e 1 2 HN N H e 1 2 NH

4 ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) N 2 O + 2 H e 1 N 2 + H 2 O H 2 N 2 O H e 1 N H 2 O 2.65 N 2 O e N 2 O H e 1 2 NHO N 2 O H e H 2 O NH 3 OH + + H e 1 N 2 H H 2 O H e 1 N 2 O + H 2 O H 2 O + 2 e 1 N 2 O + 2 OH 0.76 H 2 + H + + e 1 + H 2 O H H e 1 H 2 N 2 O H 2 O H H e 1 N 2 O + 3 H 2 O H 2 O + e OH H 2 O + 4 e 1 N 2 O OH H 2 O + 4 e 1 N 2 O + 6 OH H e 1 H 2 + H 2 O H e H 2 O H e 1 N 2 O H 2 O H 2 O + 2 e OH H 2 O + 2 e 1 N 2 O OH 0.85 Na + + e 1 Na 2.71 Nb e 1 Nb NbO H e 1 NbO + H 2 O NbO H e 1 Nb + 2 H 2 O NbO + 2 H e 1 Nb + H 2 O Nb 2 O H e 1 2 Nb + 5 H 2 O Nd e 1 Nd Nd e 1 Nd 2.1 Nd 3+ + e 1 Nd Ni e 1 Ni Ni(OH) e 1 Ni + 2 OH 0.72 NiO H e 1 Ni H 2 O NiO H 2 O + 2 e 1 Ni(OH) OH No 3+ + e 1 No No e 1 No 1.20 No e 1 No 2.50 Np e 1 Np Np 4+ + e 1 Np NpO 2 + H 2 O + H + + e 1 Np(OH) O H e 1 H 2 O O H e 1 2 H 2 O O 2 + H 2 O + 2 e 1 HO 2 + OH O H 2 O + 2 e 1 H 2 O OH O H 2 O + 4 e 1 4 OH O H e 1 O 2 + H 2 O O 3 + H 2 O + 2 e 1 O OH 1.24 O(g) + 2 H e 1 H 2 O OH + e 1 OH 2.02 HO 2 + H 2 O + 2 e 1 3 OH OsO H e 1 Os + 4 H 2 O OsO H e 1 OsO H 2 O 1.02 [Os(bipy) 2 ] 3+ + e 1 [Os(bipy) 2 ] [Os(bipy) 3 ] 3+ + e 1 [Os(bipy) 3 ] P(red) + 3 H e 1 PH 3 (g) P(white) + 3 H e 1 PH 3 (g) 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 H 3 PO H e 1 H 3 PO 2 + H 2 O H 3 PO H e 1 P + 3 H 2 O HPO H 2 O + 2 e 1 H 2 PO OH 1.65 HPO H 2 O + 3 e 1 P + 5 OH 1.71 H 3 PO H e 1 H 3 PO 3 + H 2 O PO H 2 O + 2 e 1 HPO OH 1.05 Pa e 1 Pa 1.34 Pa e 1 Pa 1.49 Pa 4+ + e 1 Pa Pb e 1 Pb Pb e 1 Pb(Hg) PbBr e 1 Pb + 2 Br PbCl e 1 Pb + 2 Cl PbF e 1 Pb + 2 F PbHPO e 1 Pb + HPO PbI e 1 Pb + 2 I PbO + H 2 O + 2 e 1 Pb + 2 OH PbO H e 1 Pb H 2 O HPbO 2 + H 2 O + 2 e 1 Pb + 3 OH PbO 2 + H 2 O + 2 e 1 PbO + 2 OH PbO 2 + SO H e 1 PbSO H 2 O PbSO e 1 Pb + SO PbSO e 1 Pb(Hg) + SO Pd e 1 Pd [PdCl 4 ] e 1 Pd + 4 Cl [PdCl 6 ] e 1 [PdCl 4 ] Cl Pd(OH) e 1 Pd + 2 OH 0.07 Pm e 1 Pm 2.2 Pm e 1 Pm 2.30 Pm 3+ + e 1 Pm Po e 1 Po Po e 1 Po 0.76 Pr 4+ + e 1 Pr Pr e 1 Pr 2.0 Pr e 1 Pr Pr 3+ + e 1 Pr Pt e 1 Pt 1.18 [PtCl 4 ] e 1 Pt + 4 Cl [PtCl 6 ] e 1 [PtCl 4 ] Cl 0.68 Pt(OH) e 1 Pt + 2 OH 0.14 PtO H e 1 PtO 2 + H 2 O 1.7 PtO H e 1 Pt(OH) H 2 O 1.5 PtOH + + H e 1 Pt + H 2 O 1.2 PtO H e 1 PtO + H 2 O 1.01 PtO H e 1 Pt + 2 H 2 O 1.00 Pu e 1 Pu Pu 4+ + e 1 Pu Pu 5+ + e 1 Pu PuO 2 (OH) H e 1 Pu(OH) PuO 2 (OH) 2 + H + + e 1 PuO 2 OH + H 2 O Ra e 1 Ra 2.8 Rb + + e 1 Rb 2.98 Re e 1 Re 0.300

5 ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) ReO H e 1 ReO H 2 O ReO H e 1 Re + 2 H 2 O ReO H + + e 1 ReO 3 + H 2 O ReO H 2 O + 7 e 1 Re + 8 OH ReO H e 1 Re + 4 H 2 O Rh + + e 1 Rh Rh + + 2e1 Rh Rh e 1 Rh [RhCl 6 ] e 1 Rh + 6 Cl RhOH 2+ + H e 1 Rh + H 2 O 0.83 Ru e 1 Ru Ru 3+ + e 1 Ru RuO H e 1 Ru H 2 O RuO 4 + e 1 RuO RuO 4 + e 1 RuO RuO H e 1 Ru(OH) H 2 O 1.40 RuO H e 1 Ru + 4 H 2 O [Ru(bipy) 3 ) 3+ + e 1 [Ru(bipy) 3 ] [Ru(H 2 O) 6 ] 3+ + e 1 [Ru(H 2 O) 6 ] [Ru(NH 3 ) 6 ] 3+ + e 1 [Ru(NH 3 ) 6 ] [Ru(en) 3 ] 3+ + e 1 [Ru(en) 3 ] [Ru(CN) 6 ] 3 + e 1 [Ru(CN) 6 ] S + 2 e 1 S S + 2H e 1 H 2 S(aq) S + H 2 O + 2 e 1 SH + OH S + 2 e 1 S S 2 O H e 1 2 H 2 SO S 2 O e 1 2 SO S 2 O H e 1 2 HSO S 4 O e 1 2 S 2 O H 2 SO 3 + H e 1 HS 2 O H 2 O H 2 SO H e 1 S + 3 H 2 O SO H 2 O + 2 e 1 S 2 O OH SO H 2 O + 4 e 1 S 2 O OH SO H e 1 H 2 SO 3 + H 2 O SO H e 1 S 2 O H 2 O 0.22 SO H 2 O + 2 e 1 SO OH 0.93 Sb + 3 H e 1 SbH Sb 2 O H e 1 2 Sb + 3 H 2 O Sb 2 O 5 (senarmontite) + 4 H e 1 Sb 2 O H 2 O Sb 2 O 5 (valentinite) + 4 H e 1 Sb 2 O H 2 O Sb 2 O H e 1 2 SbO H 2 O SbO H e 1 Sb + 2 H 2 O SbO H 2 O + 3 e 1 Sb + 4 OH 0.66 SbO 3 + H 2 O + 2 e 1 SbO OH 0.59 Sc e 1 Sc Se + 2 e 1 Se Se + 2 H e 1 H 2 Se(aq) H 2 SeO H e 1 Se + 3 H 2 O 0.74 Se + 2 H e 1 H 2 Se SeO H 2 O + 4 e 1 Se + 6 OH SeO H e 1 H 2 SeO 3 + H 2 O SeO H 2 O + 2 e 1 SeO OH 0.05 SiF e 1 Si + 6 F 1.24 SiO + 2 H e 1 Si + H 2 O 0.8 SiO 2 (quartz) + 4 H e 1 Si + 2 H 2 O SiO H 2 O + 4 e 1 Si + 6 OH Sm 3+ + e 1 Sm Sm e 1 Sm Sm e 1 Sm 2.68 Sn e 1 Sn Sn e 1 Sn Sn(OH) H e 1 Sn H 2 O SnO H e 1 Sn H 2 O SnO H e 1 Sn + 2 H 2 O SnO H e 1 SnOH + + H 2 O SnO H 2 O + 4 e 1 Sn + 4 OH HSnO 2 + H 2 O + 2 e 1 Sn + 3 OH Sn(OH) e 1 HSnO OH + H 2 O 0.93 Sr + + e 1 Sr 4.10 Sr e 1 Sr Sr e 1 Sr(Hg) Sr(OH) e 1 Sr + 2 OH 2.88 Ta 2 O H e 1 2 Ta + 5 H 2 O Ta e 1 Ta 0.6 Tc e 1 Tc TcO H e 1 TcO H 2 O Tc 3+ + e 1 Tc TcO H e 1 Tc + 4 H 2 O Tb 4+ + e 1 Tb Tb e 1 Tb 2.28 Te + 2 e 1 Te Te + 2 H e 1 H 2 Te Te e 1 Te TeO H e 1 Te + 2 H 2 O TeO H 2 O + 4 e 1 Te + 6 OH 0.57 TeO H e 1 Te + 4 H 2 O H 6 TeO H e 1 TeO H 2 O 1.02 Th e 1 Th ThO H e 1 Th + 2 H 2 O Th(OH) e 1 Th + 4 OH 2.48 Ti e 1 Ti Ti 3+ + e 1 Ti TiO H e 1 Ti H 2 O Ti e 1 Ti 1.37 TiOH 3+ + H + + e 1 Ti 3+ + H 2 O Tl + + e 1 Tl Tl + + e 1 Tl(Hg) Tl e 1 Tl Tl e 1 Tl TlBr + e 1 Tl + Br TlCl + e 1 Tl + Cl TlI + e 1 Tl + I Tl 2 O H 2 O + 4 e 1 2 Tl OH 0.02 TlOH + e 1 Tl + OH 0.34 Tl(OH) e 1 TlOH + 2 OH 0.05 Tl 2 SO e 1 Tl + SO Tm 3+ + e 1 Tm Tm e 1 Tm Tm e 1 Tm 2.4

6 ELECTROCHEMICAL SERIES (continued) TABLE 1 Alphabetical Listing (continued) U e 1 U U 4+ + e 1 U UO H + + e 1 U H 2 O UO e 1 UO UO H e 1 U H 2 O UO H e 1 U + 2 H 2 O V e 1 V V 3+ + e 1 V VO H + + e 1 V 3+ + H 2 O VO H + + e 1 VO 2+ + H 2 O V 2 O H e 1 2 VO H 2 O V 2 O H e 1 2 V + 5 H 2 O V(OH) H + + e 1 VO H 2 O 1.00 V(OH) H e 1 V + 4 H 2 O [V(phen) 3 ] 3+ + e 1 [V(phen) 3 ] W e 1 W 0.1 W 2 O H e 1 2 WO 2 + H 2 O WO H e 1 W + 2 H 2 O WO H e 1 W + 3 H 2 O WO H e 1 WO 2 + H 2 O WO H e 1 W 2 O 5 + H 2 O H 4 XeO H e 1 XeO H 2 O 2.42 XeO H e 1 Xe + 3 H 2 O 2.10 XeF + e 1 Xe + F 3.4 Y e 1 Y Yb 3+ + e 1 Yb Yb e 1 Yb 2.19 Yb e 1 Yb 2.76 Zn e 1 Zn Zn e 1 Zn(Hg) ZnO H 2 O + 2 e 1 Zn + 4 OH ZnSO 4 7 H 2 O + 2 e = Zn(Hg) + SO H 2 O (Saturated ZnSO 4 ) ZnOH + + H e 1 Zn + H 2 O Zn(OH) e 1 Zn + 4 OH Zn(OH) e 1 Zn + 2 OH ZnO + H 2 O + 2 e 1 Zn + 2 OH ZrO H e 1 Zr + 2 H 2 O ZrO(OH) 2 + H 2 O + 4 e 1 Zr + 4 OH 2.36 Zr e 1 Zr 1.45 TABLE 2 Reduction s Having E Values More Positive than that of the Standard Hydrogen Electrode 2 H e 1 H CuI 2 + e 1 Cu + 2 I 0.00 Ge e 1 Ge H 2 O + 2 e OH 0.01 Tl 2 O H 2 O + 4 e 1 2 Tl OH 0.02 SeO H 2 O + 2 e 1 SeO OH 0.05 WO H e 1 WO 2 + H 2 O UO e = UO Pd(OH) e 1 Pd + 2 OH 0.07 AgBr + e 1 Ag + Br MoO H e 1 Mo + 3 H 2 O S 4 O e 1 2 S 2 O H 3 Mo 7 O H e 1 7 Mo + 24 H 2 O AgSCN + e 1 Ag + SCN N H 2 O + 6 H e 1 2 NH 4 OH HgO + H 2 O + 2 e 1 Hg + 2 OH Ir 2 O H 2 O + 6 e 1 2 Ir + 6 OH e 1 N 2 O [Ru(NH 3 ) 6 ] 3+ + e 1 [Ru(NH 3 ) 6 ] W e 1 W 0.1 [Co(NH 3 ) 6 ] 3+ + e 1 [Co(NH 3 ) 6 ] Hg 2 O + H 2 O + 2 e 1 2 Hg + 2 OH Ge e 1 Ge Hg 2 Br e 1 2 Hg + 2 Br Pt(OH) e 1 Pt + 2 OH 0.14 [V(phen) 3 ] 3+ + e 1 [V(phen) 3 ] S + 2H e 1 H 2 S(aq) Sn(OH) H e 1 Sn H 2 O Np 4+ + e 1 Np Ag 4 [Fe(CN) 6 ] + 4 e 1 4 Ag + [Fe(CN) 6 ] IO H 2 O + 4 e 1 IO + 4 OH 0.15 Mn(OH) 3 + e 1 Mn(OH) 2 + OH H 2 O + 4 e 1 N 2 O + 6 OH 0.15 Sn e 1 Sn Sb 2 O H e 1 2 Sb + 3 H 2 O Cu 2+ + e 1 Cu BiOCl + 2 H e 1 Bi + Cl + H 2 O BiCl e 1 Bi + 4 Cl 0.16 Fe 2 O H e 1 2 FeOH + + H 2 O 0.16 Co(OH) 3 + e 1 Co(OH) 2 + OH 0.17 SO H e 1 H 2 SO 3 + H 2 O Bi e 1 Bi [Ru(en) 3 ] 3+ + e 1 [Ru(en) 3 ] SbO H e 1 Sb + 2 H 2 O AgCl + e 1 Ag + Cl [Ru(H 2 O) 6 ] 3+ + e 1 [Ru(H 2 O) 6 ] As 2 O H e 1 2 As + 3 H 2 O Calomel electrode, saturated NaCl (SSCE) Ge e 1 Ge 0.24 Ru 3+ + e 1 Ru Calomel electrode, saturated KCl PbO 2 + H 2 O + 2 e 1 PbO + 2 OH HAsO H e 1 As + 2 H 2 O Ru 3+ + e 1 Ru

7 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, c/mol L 1 HF HCl HBr HI Inf. dil 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

8 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

9 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, 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, Pratt, K.W., Koch, W.F., Wu, Y.C., and Berezansky, P.A., Pure Appl. Chem. 73, 1783, k/s m -1 t/ C 0.01 m KCl 0.1 m KCl 1.0 m KCl H 2 O (CO 2 sat.)

10 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 = and B = Λ can be found from the next table, Ionic Conductivity and Diffusion at Infinite Dilution. The equation is reliable for c < mol/l; with higher concentration the error increases. Concentration (mol/l) Infinite Compound dilution Λ Λ Ag /2BaCl /2CaCl /2Ca(OH) /2CuSO HCl KBr KCl K /3K 3 Fe(CN) /4K 4 Fe(CN) KHCO KI KIO K KMnO KOH KReO /3LaCl LiCl Li /2MgCl NH 4 Cl NaCl Na NaI NaOOCCH NaOH Na picrate /2Na 2 SO /2SrCl /2ZnSO

11 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, Robinson, R. A., and Stokes, R. H., Electrolyte Solutions, Butterworths, London, Lobo, V. M. M., and Quaresma, J. L., Handbook of Electrolyte Solutions, Physical Science Data Series 41, Elsevier, Amsterdam, Conway, B. E., Electrochemical Data, Elsevier, Amsterdam, Milazzo, G., Electrochemistry: Theoretical Principles and Practical Applications, Elsevier, Amsterdam, λ D Ion 10-4 m 2 S mol cm 2 s -1 Inorganic Cations Ag /3Al /2Ba /2Be /2Ca /2Cd /3Ce /2Co /3[Co(NH 3 ) 6 ] /3[Co(en) 3 ] /6[Co 2 (trien) 3 ] /3Cr Cs /2Cu D /3Dy /3Er /3Eu /2Fe /3Fe /3Gd H /2Hg /2Hg λ D Ion 10-4 m 2 S mol cm 2 s -1 1/3Ho K /3La Li /2Mg /2Mn NH N 2 H Na /3Nd /2Ni /4[Ni 2 (trien) 3 ] /2Pb /3Pr /2Ra Rb /3Sc /3Sm /2Sr Tl /3Tm /2UO /3Y /3Yb /2Zn

12 IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION (continued) λ D λ D Ion 10-4 m 2 S mol cm 2 s -1 Ion 10-4 m 2 S mol cm 2 s -1 Inorganic Anions Au(CN) Au(CN) B(C 6 H 5 ) Br Br BrO CN C /2CO Cl /3[Co(CN) 6 ] /2CrO F /4[Fe(CN) 6 ] /3[Fe(CN) 6 ] H 2 AsO HCO HF /2HPO H 2 PO H 2 PO HS HSO HSO H 2 SbO I IO IO MnO /2MoO N(CN) NH 2 SO N OCN OD OH PF /2PO 3 F /3PO /4P 2 O /3P 3 O /5P 3 O ReO SCN /2SO /2SO /2S 2 O /2S 2 O /2S 2 O /2S 2 O Sb(OH) SeCN /2SeO /2WO Organic Cations Benzyltrimethylammonium Isobutylammonium Butyltrimethylammonium Decylpyridinium Decyltrimethylammonium Diethylammonium Dimethylammonium Dipropylammonium Dodecylammonium Dodecyltrimethylammonium Ethanolammonium Ethylammonium Ethyltrimethylammonium Hexadecyltrimethylammonium Hexyltrimethylammonium Histidyl Hydroxyethyltrimethylarsonium Methylammonium Octadecylpyridinium Octadecyltributylammonium Octadecyltriethylammonium Octadecyltrimethylammonium Octadecyltripropylammonium Octyltrimethylammonium Pentylammonium Piperidinium Propylammonium Pyrilammonium Tetrabutylammonium Tetradecyltrimethylammonium Tetraethylammonium Tetramethylammonium Tetraisopentylammonium Tetrapentylammmonium Tetrapropylammonium Triethylammonium Triethylsulfonium Trimethylammonium Trimethylhexylammonium Trimethylsulfonium Tripropylammonium Organic Anions Acetate p-anisate /2Azelate Benzoate Bromoacetate Bromobenzoate Butyrate Chloroacetate m-chlorobenzoate o-chlorobenzoate

13 IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION (continued) λ D λ D Ion 10-4 m 2 S mol cm 2 s -1 Ion 10-4 m 2 S mol cm 2 s -1 1/3Citrate Crotonate Cyanoacetate Cyclohexane carboxylate /2 1,1-Cyclopropanedicarboxylate Decylsulfate Dichloroacetate /2Diethylbarbiturate Dihydrogencitrate /2Dimethylmalonate ,5-Dinitrobenzoate Dodecylsulfate Ethylmalonate Ethylsulfate Fluoroacetate Fluorobenzoate Formate /2Fumarate /2Glutarate Hydrogenoxalate Isovalerate Iodoacetate Lactate /2Malate /2Maleate /2Malonate Methylsulfate Naphthylacetate /2Oxalate Octylsulfate Phenylacetate /2o-Phthalate /2m-Phthalate Picrate Pivalate Propionate Propylsulfate Salicylate /2Suberate /2Succinate p-sulfonate /2Tartarate Trichloroacetate