Question

The reaction of Cr³⁺(aq) and Cr(s) to form Cr²⁺(aq). [The reduction potential of Cr²⁺(aq) to Cr(s) is -0.91 V.]

If ΔG∘rxn = -79 kJ, Calculate K.

Answer 1

The equilibrium constant K for the reaction can be calculated using the standard Gibbs free energy change and the standard cell potential, along with the Nernst equation at standard conditions.

Step-by-step explanation:

The question asks to calculate the equilibrium constant K for the reaction of Cr3+(aq) and Cr(s) to form Cr2+(aq), using the information that the change in standard Gibbs free energy ΔGorxn is -79 kJ, and the reduction potential for Cr2+(aq) to Cr(s) is -0.91 V. To calculate K, we can use the Nernst equation at standard conditions (Eo = 0) and the relationship between ΔGo and the equilibrium constant (ΔGo = -RTlnK, where R is the gas constant and T is temperature in Kelvin).

The standard Gibbs free energy is related to the standard cell potential Eocell by the equation ΔGo = -nFEocell, where n is the number of moles of electrons transferred and F is the Faraday constant. Since we have the values for ΔGorxn and Eocell, we can find K using these relationships.