A rechargeable battery is classified as a secondary battery. Nickel-iron battery is an example of a secondary battery. Its half-reactions occur as follows:

Cathode:   NiO(OH) (s) + H₂O (l) + e⁻ → Ni(OH)₂ (s) + OH⁻ (aq)

Anode:      Fe (s) + 2 OH⁻ (aq) → Fe(OH)₂ (s) + 2 e⁻

Given the following data, determine the standard cell potential for the nickel-iron battery:

NiO(OH) (s) + H₂O (l) + e⁻ → Ni(OH)₂ (s) + OH⁻ (aq); E°_red = 0.52 V

Fe²⁺ (aq) + 2 e^– → Fe (s); E°_red = −0.447 V

Fe(OH)₂ (s) → Fe²⁺ (aq) + 2 OH^– (aq); K_sp = 4.87×10^–17

Molten carbonate fuel cells (MCFC) are newly developed fuel cells that commonly use molten lithium and potassium carbonates as electrolytes. The half-reactions in the cell are shown below: 

Anode: H₂(g) + CO₃^2–(l) → H₂O(l) + CO₂(g) + 2 e^–

Cathode: 1/2 O₂(g) + CO₂(g) + 2 e^– → CO₃^2–(l)

Using the thermodynamic values below, determine the cell potential (E°) and the equilibrium constant (K) for the overall reaction at 25°C. Identify whether the values of E° and K will increase, decrease or remain unchanged as the temperature decreases. 

What are the balanced equation, standard emf, ΔG°, and K value at 298 K for the oxidation of MnO₂(s) to MnO₄⁻(aq) by ClO⁻(aq) in basic solution?

Silver is extracted from its ore via the leaching process for the cyanide ion in that ore. Shown below is the overall reaction.

4 Ag (s) + 8 CN⁻ (aq)  + O₂ (g) + 2 H₂O (l) → 4 [Ag(CN)₂]⁻ (aq) + 4 OH⁻ (aq)

Use the given data to calculate ΔG° for the above reaction at 25 °C.

Ag⁺ (aq) + 2 CN⁻ (aq) → Ag(CN)₂⁻ (aq);    K_f = 3.00×10²⁰

H₂O (l) ⇌ H⁺ (aq) + OH⁻ (aq);                   K_w = 1.00×10⁻¹⁴ 

O₂ (g) + 4 H⁺ (aq) + 4 e⁻ → 2 H₂O (l);        E° = 1.229 V

Ag⁺ (aq) + e⁻ → Ag (s);                              E° = 0.800 V