What is the value of the equilibrium constant at 25 oC for the reaction between the pair: Fe(s) and Cr3 (aq) to give Cr(s) and Fe2 (aq). Give your answer using E-notation with NO decimal places (e. g., 2 x 10-2 would be 2E-2; and 2.12 x 10-2 would also be 2E-2.). Do NOT include spaces, units, punctuation or anything else silly! Use the reduction potentials for Cr3 (aq) is -0.74 V and for Fe2 (aq) is -0.440 V. [a]

The equilibrium constant is

Explanation:

   From the question we are told that

        The reduction potential of =

        The reduction potential of   =        

      In order for us to obtain the equilibrium constant we need to understand the process of the reaction

   At the cathode is reduced to Cr the reaction is  

   At the anode is oxidized to the reaction is

The net voltage of the cell is mathematically given as

  substituting value

Next we need to mathematically evaluate the  free energy of the cell as

where is the number of moles of  electron which is  6

           F is the farad constant with a value  

Substituting values

The equilibrium constant is mathematically represented as

Where R is the gas constant with value  8.314 J/mol

            T is the temperature with a given value of  

Substituting values