Assume that the net reaction for the following cell occurs i

Assume that the net reaction for the following cell occurs in the direction consistent with the way the cell is written (anode on the left and cathode on the right). Calculate the standard cell potential.

Cr(s) | Cr³⁺(aq) || Cu²⁺(aq) | Cu(s)

______V

Repeat the exercise with the following cell:

Ag(s) | Ag⁺(aq) || Cd²⁺(aq) | Cd(s)

_______V

Which reaction(s) is(are) product favored (spontaneous)?

1.Both

2.Reaction1

3.Reaction2

4.Neither

Solution

reduction: Cr3+(aq) + 3 e– --> Cr(s) Eo = – 0.74
reduction: Cu2+(aq) + 2 e– --> Cu(s) Eo = + 0.340

your reaction uses:
oxidation: Cr(s) --> Cr3+(aq) + 3 e– Eo = + 0.74
reduction: Cu2+(aq) + 2 e– --> Cu(s) Eo = + 0.340

your standard reduction potential for
Cr(s) | Cr3+(aq) || Cu2+(aq) | Cu(s)
would be
Eo = 1.08 volts
(since it is a positive voltage, it is spontaneous)

reduction: Ag+(aq) + e– --> Ag(s) Eo = 0.800
reduction: Cd2+(aq) + 2 e– --> Cd(s) Eo = –0.403

your reaction has it as
oxidation: Ag(s) --> --Ag+(aq) + e– - Eo = - 0.800
reduction: Cd2+(aq) + 2 e– --> Cd(s) Eo = –0.403

your standard reduction potential for
Ag(s) | Ag+(aq) || Cd2+(aq) | Cd(s)?
would be
Eo = - 1.203 volts
(since it is a negative voltage, it is not spontaneous)