Question

The Nernst equation is one of the most important equations in electrochemistry. To calculate the cell potential at non-standard-state conditions, the equation is

E=E∘−2.303RTnFlog10Q

where E is the potential in volts, E∘ is the standard potential in volts, R is the gas constant, T is the temperature in kelvins, n is the number of moles of electrons transferred, F is the Faraday constant, and Q is the reaction quotient. At standard temperature, 25 ∘C or 298 K, the equation has the form

E=E∘−(0.0592n)logQ

The reaction quotient has the usual form

Q=[products]x[reactants]y

A table of standard reduction potentials gives the voltage at standard conditions, 1.00 M for all solutions and 1.00 atm for all gases. The Nernst equation allows for the calculation of the cell potential E at other conditions of concentration and pressure.

Part A

For the reaction

2Co3+(aq)+2Cl−(aq)→2Co2+(aq)+Cl2(g). E∘=0.71 V

what is the cell potential at 25 ∘C if the concentrations are [Co3+]= 0.729 M , [Co2+]= 0.132 M , and [Cl−]= 0.676 M and the pressure of Cl2 is PCl2= 9.80 atm ?