“A solution holds $\text{Cu}^{2+}$, $\text{Fe}^{2+}$ and $\text{Zn}^{2+}$, each at the same concentration. The cathode potential is lowered slowly. The standard potentials are $+0.34\ \text{V}$, $-0.44\ \text{V}$ and $-0.76\ \text{V}$. In what order do the metals deposit?” is available to Standard subscribers.