Question

What is the standard reduction potential of the Y3+/Y redox couple if the cell potential of the following cell at 25 oC is 1.08 V? Zn / Zn2+ (0.42 M) // Y3+ (1.2 M) / Y

Eo = ____ V

Incorrect: .279 is incorrect.

Answer 1

Given:

Cell potential = 1.08 V

Cell : Zn / Zn2+ (0.42 M) // Y3+ (1.2 M) / Y

Lets write half oxidation and reduction.

[Zn²⁺]=0.42 M, [Y³⁺]=1.2 M

Overall cell reaction

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From this reaction, we can determine number of electrons involved and #e- = 6

We use Nernst equation and find standard cell potential

n = 6 , oxidant is Zn²⁺ and reductant is Y³⁺.

Lets plug given values in above equation to get standard cell potential

We know

E⁰ of Zn²⁺/Zn = -0.762 V

Zn is anode so we put for Ea and find Ec⁰ (cathode)

Ans : Standard redcution potential of Y³⁺ /Y is 0.313 V