Question

If the standard electrode potential of cu2+/cu electrode is 0.34 v, what is the electrode potential of 0.1 M concentration of cu2+ ?

Answer 1

Answer:

If the activity of the hydrogen ion is 1 mol/l (pH=0) and hydrogen gas is bubbled into the solution so that partial pressure of hydrogen is 1 atm, the electrode potential is defined as zero volts at any temperature: E0=0.000 V.

Answer 2

The electrode potential of Cu2+/Cu couple in the given conditions is 0.31045 V.

• According to the Nernst equation:

          E = Eo  - (RT/nF) ln{[P]/[R]}

          where, Eo = standard electrode potential

                       E = electrode potential

                       R = gas constant

                       T = temperature

                       n = number of electrons

                       P = activity (concentration) of products

                       R = activity (concentration) of reactants

• At room temperature,  E = Eo - (0.0591/n) log{[P]/[R]}
• Substituting the values as: n = 2, [P] = 1 (since for metals, activity = 1), [R] = 0.1 (given),  Eo = 0.34 V (given)

                 E = 0.31045 V