Question

Consider a galvanic cell that uses the half reactions, 

2H⁺_(aq)  + 2e^- → H_(g)

Mg²⁺_(aq) + 2e^- → Mg_(s)

Write balanced equation for the cell reaction. 

Calculate E⁰_Cell, E_Cell and ΔG⁰ if concentrations are 1M each and \(P_{H_2}\) = 10 atm

\(E^0_{Mg^{2+}/Mg}\) = -2.37 V.

Answer 1

Given,

For the reactions, the half cells with be :

The formulation of the cell will be,

Mg electrode will be anode and H₂ gas electrode will be cathode.

The standard free energy change ΔG⁰  is given by,

ΔG⁰ = – nFE⁰_cell 

= – 2 × 96500 × 2.37 

= -457400 J 

= – 457.4 kJ

∴ E⁰_cell = 2.37 V; 

E_cell = 2.3404 V;

ΔG⁰ = -457.4 kJ