Write the balanced equation for the overall reaction in acidic solution.

Question

Consider a galvanic electrochemical cell constructed using Cr/Cr³⁺ and Zn/Zn²⁺ at 25 °C. The following half-reactions are provided for each metal: Cr³⁺(aq) + 3 e⁻ → Cr(s) E°red = -0.744 V Zn²⁺(aq) + 2 e⁻ → Zn(s) E°red = -0.763 V

Answer 1

Cr³⁺(aq) + 3 e⁻ → Cr(s) E°red = -0.744 This will be the reduction reaction at the cathode

Zn²⁺(aq) + 2 e⁻ → Zn(s) E°red = -0.763 V This will be the oxidation reaction at the anode

Cr³⁺(aq) + 3e- ==> Cr(s) ... Eº = -0.744 (cathode)

Zn(s) ==>Zn²⁺(aq) + 2e- ... Eº = -0.763 (anode)

Balanced overall reaction so electrons are equal:

2Cr³⁺(aq) + 3Zn(s) + 6e- ==> 2Cr(s) + 3Zn²⁺(aq) + 6e-

Not sure why they asked for acidic solution as there are no hydrogens or oxygens that enter into the redox equation.