Question

What is the correct Nernst equation for M^2+ (aq) + 2e^+ → M (s) at 45°C?

(a) E°(M2+/M) + 0.315log10 (1 / [M]^+2)

(b) E° (M2+/M) + 0.0425log10 (1 / [M]^+2)

(c) E° (M2+/M) + 0.0315log10 (1 / [M]^+2)

(d) E° (M2+/M) + 0.0326log10 (1 / [M]^+2)

I have been asked this question by my college professor while I was bunking the class.

This interesting question is from Electrochemistry in division Electrochemistry of Chemistry – Class 12

Answer 1

Correct answer is (c) E° (M2+/M) + 0.0315log10 (1 / [M]^+2)

The best I can explain: Given, Temperature T = 45°C

We know, n (number of electrons transferred) = 2

According to Nernst equation, E(M2+/M) = E° (M2+/M) +2.303\(\frac{RT}{nF}\)log10 (M / [M]^+2)

Concentration of [M] is taken to be 1

The equation becomes: E° (M2+/M) +2.303 \(\frac{RT}{nF}\)log10 (1/[M]^+2)

E(M2+/M) = E° (M2+/M) +2.303 × \(\frac{8.314 \times 318}{2 \times 96500}\)log10 (1 / [M]^+2) =E° (M2+/M) + 0.0315log10 (1 / [M]^+2).