Ni-cad (nickel-cadmium) batteries have a slightly lower cell potential than the common alkaline value of 1.5 v normally used in flashlights. they have a cadmium anode, which is oxidized to cd (oh) 2 (s) in a basic background electrolyte of concentrated oh-, and a cathode half-reaction in which nio (oh) (s) is reduced to ni (oh) 2 (s). what is the value of δg°cell?

Question

Trujillo

Chemistry

10 May, 12:33

Ni-cad (nickel-cadmium) batteries have a slightly lower cell potential than the common alkaline value of 1.5 v normally used in flashlights. they have a cadmium anode, which is oxidized to cd (oh) 2 (s) in a basic background electrolyte of concentrated oh-, and a cathode half-reaction in which nio (oh) (s) is reduced to ni (oh) 2 (s). what is the value of δg°cell?

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Gerardo Mcgee · Answer 1

The half-reaction are:

Cd - - - > Cd (OH) ₂

The oxidation number of Cd changed from 0 to + 2. So, the number of mol electron transferred here is 2.

NiO (OH) - - > Ni (OH) ₂

The oxidation number of Cd changed from + 3 to + 2. So, the number of mol electron transferred here is 1.

Now, the greatest common factor would be 2. So, we use n=2 for the formula for ΔG°. F is Faraday's constant equal to 96,485 J/mol e.

ΔG° = nFE° = (2) (96,485) (1.5) = 289,455 J