複選題

24. The following half-cells for which the reduction reaction and its corresponding standard electromotive force $(\mathrm{E}^{\circ})$ is given by

Half-cell (a): $\mathrm{Fe(OH)_{2(s)} + 2e^{-} \rightarrow Fe_{(s)} + 2OH^{-}(aq)}$ $\quad \mathrm{E}^{\circ} = -0.877\,\mathrm{V}$

Half-cell (b): $\mathrm{Al}^{3+}(aq) + 3e^{-} \rightarrow \mathrm{Al}_{(s)}$ $\quad \mathrm{E}^{\circ} = -1.66\,\mathrm{V}$

Half-cell (c): $\mathrm{AgBr}_{(s)} + \mathrm{e}^{-} \rightarrow \mathrm{Ag}_{(s)} + \mathrm{Br}^{-}_{(aq)}$ $\quad \mathrm{E}^{\circ} = +0.071\,\mathrm{V}$

The electrochemical cell 1 $(\mathbf{E}_1)$ is constructed with the half-cell (a) and (b), whereas the electrochemical cell 2 $(\mathbf{E}_2)$ is constructed with the half-cell (a) and (c). The activity of all species is one for both cells. Which of the following statements are correct?
(A) The electromotive force of the electrochemical cell is positive when the electrochemical reaction is spontaneous.
(B) In $\mathrm{E}_1$, $\mathrm{Fe}_{(s)}$ is oxidized.
(C) In $\mathrm{E}_2$, $\mathrm{Fe}_{(s)}$ is reduced.
(D) If $\mathrm{E}_1$ is spontaneous, the overall reaction is $3\mathrm{Fe(OH)}_{2(s)} + 2\mathrm{Al}_{(s)} \rightleftharpoons 3\mathrm{Fe}_{(s)} + 6\mathrm{OH}^{-}_{(aq)} + \mathrm{Al}^{3+}_{(aq)}$.


(E) If $\mathrm{E}_2$ is spontaneous, the overall reaction is $\mathrm{Fe(OH)}_{2(s)} + 2\mathrm{Ag}_{(s)} + 2\mathrm{Br}^{-}_{(aq)} \rightleftharpoons \mathrm{Fe}_{(s)} + 2\mathrm{OH}^{-}_{(aq)} + 2\mathrm{AgBr}_{(s)}$.