(a) Assuming standard conditions, arrange the following in order of increasing strength as oxidizing agents in acidic solution: \(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}, \mathrm{H}_{2} \mathrm{O}_{2}, \mathrm{Cu}^{2+}, \mathrm{Cl}_{2}, \mathrm{O}_{2} .\) (b) Arrange the following in order of increasing strength as reducing agents in acidic solution: \(\text {Zn,}\) \(\mathrm{I}^{-}, \mathrm{Sn}^{2+}, \mathrm{H}_{2} \mathrm{O}_{2}, \mathrm{Al} .\)

First, we need to find the standard reduction potentials (E°) for the given half-cell reactions. We can do this by consulting a table of standard reduction potentials. (a) For the oxidizing agents in acidic solution: - \(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}+ 14\mathrm{H}^{+}+ 6\mathrm{e}^{-} \longrightarrow 2\mathrm{Cr}^{3+} + 7H_{2}O\), E° = 1.33 V - \(\mathrm{H}_{2} \mathrm{O}_{2} + 2\mathrm{H}^{+} + 2\mathrm{e}^{-} \longrightarrow 2\mathrm{H}_{2}\mathrm{O}\), E° = 1.78 V - \(\mathrm{Cu}^{2+} + 2\mathrm{e}^{-} \longrightarrow \mathrm{Cu}\), E° = 0.34 V - \(\mathrm{Cl}_{2} + 2\mathrm{e}^{-} \longrightarrow 2\mathrm{Cl}^-\), E° = 1.36 V - \(\mathrm{O}_{2} + 4\mathrm{H}^{+} + 4\mathrm{e}^{-} \longrightarrow 2\mathrm{H}_{2}\mathrm{O}\), E° = 1.23 V (b) For the reducing agents in acidic solution: - \(\text {Zn} + 2\mathrm{H}^{+} \longrightarrow \mathrm{Zn}^{2+}+ \mathrm{H}_{2}\), E° = -0.76 V - \(2\mathrm{I}^{-} \longrightarrow \mathrm{I}_{2}+ 2\mathrm{e}^{-}\), E° = 0.54 V - \(\mathrm{Sn}^{2+} + 2\mathrm{e}^{-} \longrightarrow \mathrm{Sn}\), E° = -0.14 V - \(\mathrm{H}_{2} \mathrm{O}_{2} + 2\mathrm{H}^{+} + 2\mathrm{e}^{-} \longrightarrow 2\mathrm{H}_{2}\mathrm{O}\), E° = 1.78 V - \(\mathrm{Al} + 3\mathrm{H}^{+} \longrightarrow \mathrm{Al}^{3+} + \frac{3}{2}\mathrm{H}_{2}\), E° = -1.66 V

Now that we have the standard reduction potentials, we can arrange the given substances in order of increasing strength as oxidizing agents. We're looking for the substances with the most positive E° values, as these will be the strongest oxidizing agents. (a) The oxidizing agents in order of increasing strength are as follows: - \(\mathrm{Cu}^{2+}\) (0.34 V) - \(\mathrm{O}_{2}\) (1.23 V) - \(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}\) (1.33 V) - \(\mathrm{Cl}_{2}\) (1.36 V) - \(\mathrm{H}_{2} \mathrm{O}_{2}\) (1.78 V)

Similarly, for reducing agents, we're looking for the substances with the most negative E° values, as these will be the strongest reducing agents. (b) The reducing agents in order of increasing strength are as follows: - \(\mathrm{H}_{2} \mathrm{O}_{2}\) (1.78 V) - \(\mathrm{I}^{-}\) (0.54 V) - \(\mathrm{Sn}^{2+}\) (-0.14 V) - \(\text {Zn}\) (-0.76 V) - \(\mathrm{Al}\) (-1.66 V)