20. Electrochemistry
Cell Potential: Standard
20. Electrochemistry Cell Potential: Standard
26PRACTICE PROBLEM
Nickel-iron batteries have less impact on the environment because nickel-iron batteries don't contain cadmium, which is considered a hazardous material. The overall cell reaction for a nickel-iron cell is:
2 NiO(OH)(s) + 2 H2O(l) + Fe(s) → 2 Ni(OH)2(s) + Fe(OH)2(s)
Which would be higher: the specific energy density of a nickel-iron battery or the specific energy density nickel-cadmium battery?
NiO(OH)(s) + H2O(l) + e− → Ni(OH)2(s) + OH−(aq) E°red = +0.49 V
Fe(OH)2(s) + 2 e− → Fe(s) + 2 OH−(aq) E°red = −0.88 V
Cd(OH)2(s) + 2 e− → Cd(s) + 2 OH−(aq) E°red = −0.81 V
Nickel-iron batteries have less impact on the environment because nickel-iron batteries don't contain cadmium, which is considered a hazardous material. The overall cell reaction for a nickel-iron cell is:
2 NiO(OH)(s) + 2 H2O(l) + Fe(s) → 2 Ni(OH)2(s) + Fe(OH)2(s)
Which would be higher: the specific energy density of a nickel-iron battery or the specific energy density nickel-cadmium battery?
NiO(OH)(s) + H2O(l) + e− → Ni(OH)2(s) + OH−(aq) E°red = +0.49 V
Fe(OH)2(s) + 2 e− → Fe(s) + 2 OH−(aq) E°red = −0.88 V
Cd(OH)2(s) + 2 e− → Cd(s) + 2 OH−(aq) E°red = −0.81 V