20. Electrochemistry

Calculate the equilibrium constant for the following reaction at 25ºC. 

Fe (s) + I₂ (s)  →  Fe²⁺ (aq) + 2 I ^– (aq)

Given the following reduction potentials: 

Fe²⁺(aq) + 2 e^–  →. Fe (s)                          E°_red = – 0.45 V

I₂ (s) + 2 e^–  →. 2 I ^– (aq)                           E°_red = + 0.54 V

A cell has a standard cell potential of +0.177 V at 298 K. What is the value of the equilibrium constant for the reaction

(a) if n = 1?

At 298 K a cell reaction has a standard cell potential of +0.17 V. The equilibrium constant for the reaction is 5.5 × 10⁵. What is the value of n for the reaction?

Using the standard reduction potentials listed in Appendix E, calculate the equilibrium constant for each of the following reactions at 298 K:

(a) Fe(s) + Ni²⁺(aq) → Fe²⁺(aq) + Ni(s)

(b) Co(s) + 2 H⁺(aq) → Co²⁺(aq) + H₂(g)

(c) 10 Br^-(aq) + 2 MnO₄^-(aq) + 16 H⁺(aq) → 2 Mn²⁺(aq) + 8 H₂O(l) + 5 Br₂(l)

A cell has a standard cell potential of +0.177 V at 298 K. What is the value of the equilibrium constant for the reaction (b) if n = 2? (c) if n = 3?