Consider the following electrolysis reactions.

(a) Calculate the voltage needed to drive the net reaction if current is negligible.
(b) Suppose that the cell has a resistance of 2.0 and a current of 100 mA. How much voltage is needed to overcome the cell resistance? This is the ohmic potential.
(c) Suppose that the anode reaction has an over-potential of 0.20 V and that the cathode overpotential is 0.40 V. What voltage is needed to overcome these effects combined with those of parts (a) and (b)?
(d) Suppose that concentration polarization occurs. [OH^-]s at the cathode surface increases to 1.0 M and [Br^-]s at the anode surface decreases to 0.010 M. What voltage is needed to overcome these effects combined with those of (b) and (c)?

Transcribed Image Text:

Cathode: H2O(l) + e H2(g, 1.0 bar) + OH+(aq, 0.10 M) Anode: Br (aq. 0.10 Mr2(l) e