Standard electrode potentials for two redox systems of a metal M\text{M}M are shown below:
M3+(aq)+3e−⇌M(s)E∘=−0.20 V \text{M}^{3+}(\text{aq}) + 3\text{e}^- \rightleftharpoons \text{M}(\text{s}) \quad E^\circ = -0.20\text{ V} M3+(aq)+3e−⇌M(s)E∘=−0.20 V M3+(aq)+e−⇌M2+(aq)E∘=+0.40 V \text{M}^{3+}(\text{aq}) + \text{e}^- \rightleftharpoons \text{M}^{2+}(\text{aq}) \quad E^\circ = +0.40\text{ V} M3+(aq)+e−⇌M2+(aq)E∘=+0.40 VWhat is the standard electrode potential for the following reduction half-reaction?
M2+(aq)+2e−⇌M(s) \text{M}^{2+}(\text{aq}) + 2\text{e}^- \rightleftharpoons \text{M}(\text{s}) M2+(aq)+2e−⇌M(s)
