Chapter 19, Problem 61GQ

Four voltaic cells are set up. In each, one half-cell contains a standard hydrogen electrode. The second half-cell is one of the following:

1. (i) Cr³⁺(aq, 1.0 M)|Cr(s)
2. (ii) Fe^a+(aq, 1.0M)|Fe(s)
3. (iii) Cu²⁺(aq, 1.0M)|Cu(s)
4. (iv) Mg²⁺(aq, 1.0M)|Mg(s)
5. (a) In which of the voltaic cells does the hydrogen electrode serve as the cathode?
6. (b) Which voltaic cell produces the highest potential? Which produces the lowest potential?