\textbf{234.} If $E^\circ$ of the reaction $\mathrm{A(s) + B^{2+}(aq) \to B^{2+}(aq) + A(s)}$ is negative, and $E^\circ$ of the reaction $\mathrm{B(s) + D^{2+}(aq) \to B^{2+}(aq) + D(s)}$ is positive, which statement is \textbf{always correct}?
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(1) The reducing power of these metals is: $\mathrm{D > A > B}$.
(2) The oxidizing power of the three metal cations is: $\mathrm{B^{2+} > D^{2+} > A^{2+}}$.
(3) The reaction $\mathrm{A(s) + D^{2+}(aq) \to A^{2+}(aq) + D(s)}$ is spontaneous under standard conditions.
(4) If the standard reduction potential of electrode D is $+0.33$ V, metal A reacts with hydrochloric acid solution.
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