Problem: Calculate the equilibrium constant for each of the reactions at 25°C.b. Br2(l) + 2 Cl−(aq) → 2 Br−(aq) + Cl2(g)Standard Electrode Potentials at 25 ∘C:Reduction Half-Reaction                                             E°(V)Pb2+(aq) + 2 e− → Pb(s)                                                -0.13Mg2+(aq)+2e− → Mg(s)                                                 -2.37Br2(l) +2e− → 2 Br−(aq)                                                  1.09Cl2(g) + 2e−→ 2 Cl−(aq)                                                  1.36MnO2(s) + 4 H+(aq) + 2e− →Mn2+(aq) + 2 H2O(l)            1.21Cu2+(aq) + 2e− → Cu(s)                                                    0.16

FREE Expert Solution

We are asked to calculate the equilibrium constant for the given reaction at 25°C. We will use the Nernst Equation to calculate the equilibrium constant. The Nernst Equation relates the concentrations of compounds and cell potential.

E°cell=RTnFln K

E°cell = cell potential, V
R = gas constant = 8.314 J/(mol·K)
T = temperature, K
n = mole e- transferred
F = Faraday’s constant, 96485 C/mol e- 
K = equilibrium constant


We will use the following steps:

Step 1. Write the two half-cell reactions and determine the half-cell potentials
Step 2. Identify the reduction half-reaction (cathode) and the anode half-reaction (anode)
Step 3Get the overall reaction by balancing the number of electrons transferred then adding the reduction half-reaction and oxidation half-reaction.
Step 4. Calculate E
°cell.
Step 5Calculate K using the Nernst Equation.


Overall reaction: Br2(l) + 2 Cl(aq) → 2 Br(aq) + Cl2(g)

86% (141 ratings)
View Complete Written Solution
Problem Details

Calculate the equilibrium constant for each of the reactions at 25°C.

b. Br2(l) + 2 Cl(aq) → 2 Br(aq) + Cl2(g)

Standard Electrode Potentials at 25 C:

Reduction Half-Reaction                                             E°(V)

Pb2+(aq) + 2 e → Pb(s)                                                -0.13

Mg2+(aq)+2e− → Mg(s)                                                 -2.37

Br2(l) +2e → 2 Br(aq)                                                  1.09

Cl2(g) + 2e→ 2 Cl−(aq)                                                  1.36

MnO2(s) + 4 H+(aq) + 2e →Mn2+(aq) + 2 H2O(l)            1.21

Cu2+(aq) + 2e → Cu(s)                                                    0.16

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the The Nernst Equation concept. You can view video lessons to learn The Nernst Equation. Or if you need more The Nernst Equation practice, you can also practice The Nernst Equation practice problems.