Page 94 - Vogel's TEXTBOOK OF QUANTITATIVE CHEMICAL ANALYSIS

2 FUNDAMENTAL THEORETICAL PRINCIPLES OF REACTIONS IN SOLUTION

Table 2.6 Standard reduction potentials at 25 "C
Half-reaction E8, volts

2e e 2F-
S:Oi + 2e e 2s04-
Co3+ +eeCoZ+
Pb4+ + 2e e PbZ+
Mn04 + 4H+ + 3e e MnO, + 2H,O
Ce4+ + e e Ce3+ (nitrate medium)
BrO; + 6H + + Se e +Br, + 3H,O
Mn04 + 8H+ + 5ee MnZ+ +4H,O
Ce4+ + e + Ce3+ (sulphate medium)
CI, + 2e e 2CI-
Cr,O:- + 14H+ + 6e e 2Cr3+ + 7H,O
Tl3+ +2eeTI+
MnO, +4H+ f2ee MnZ+ +2H,O
02+4H+ +4ee2H20
IO; +6H+ + 5ee+I, + 3H,O
Br, + 2e e 2Br-
HNO,+H++eeNO+H,O
NO; +4H+ + 3ee NO +2H,O
2Hg2+ + 2e e Hg:+
CIO- +H,O +2eeCI- +20H-
Cu2++I-+eeCuI
Hg:+ + 2e e 2Hg
Fe3+ + e e FeZ+
BrO- + H,O + 2e e Br- + 20H-
BrO; + 3H20 f6ee Br- +60H-
Mn04- + 2H20 + 2ee MnO, +40H-
Mn04 + e e Mn04-
H3As04 +2H+ +2ee H3As03 +H,O
CuZ+ +CI- +eeCuCl
12+2ee21-
IO-+H20+2eeI- +20H-
[Fe(CN),13- + e % [Fe(CN),I4-
UO:++4H++2eeU4++2H20
IO; +3H20+6eeI- +60H-
Cu2++eeCu+
Sn4+ +2eeSnZ+
TiOZ+ +2H+ +eeTi3+ + H,O
S40i- + 2e e 2S,O:-
2H++2eeH2
V3+ +eeVZ+
Cr3+ +eeCrZ+
Bi(OH), + 3e e Bi + 30H -
Fe(OH), + e e Fe(OH), +OH-
U4+ +eeU3+
Asoz- +3H20+2ee H,AsO; +40H-
[Sn(OH),I2- + 2e e [HSnO,]- + H,O + 30H-
[Zn(OH),I2- + 2e e Zn + 40H -
[H,AI03]- + H,O + 3e e Al +40H-

relative to the standard or normal hydrogen electrode taken as zero potential,
Ee is the standard reduction potential,* n the number of electrons gained by

* E0 is the value of E, at unit activities of the oxidant and reductant. If both activities are variable,
e.g. Fe3+ and FeZ+, Ee corresponds to an activity ratio of unity.