Problem 44 - Chemistry The Central Science

Question

From each of the following pairs of substances, use data in Appendix \(\mathrm{E}\) to choose the one that is the stronger oxidizing agent: (a) \(\mathrm{Cl}_{2}(g)\) or \(\mathrm{Br}_{2}(l)\) (b) \(\mathrm{Zn}^{2+}(a q)\) or \(\mathrm{Cd}^{2+}(a q)\) (c) \(\mathrm{Cl}^{-}(a q)\) or \(\mathrm{ClO}_{3}^{-}(a q)\) (d) \(\mathrm{H}_{2} \mathrm{O}_{2}(a q)\) or \(\mathrm{O}_{3}(g)\)

Step-by-Step Solution

Answer

The stronger oxidizing agents for each pair are as follows: (a) Cl₂(g), (b) Cd²⁺(aq), (c) ClO₃⁻(aq), and (d) O₃(g).

Step 1: Look up Standard Reduction Potential values

From the given Appendix E, find the standard reduction potential values for each substance in the pairs provided. 3. Repeat this process for all pairs Once you've found the stronger oxidizing agent in each pair, repeat the process for all four pairs of substances.

Step 2: Solution

Step 3: (a) Cl₂(g) or Br₂(l)

Look up the values in Appendix E Standard reduction potential for Cl₂(g): \(+1.36 \ \mathrm{V}\) Standard reduction potential for Br₂(l): \(+1.07 \ \mathrm{V}\) Since Cl₂(g) has a higher reduction potential, it is the stronger oxidizing agent.

Step 4: (b) Zn²⁺(aq) or Cd²⁺(aq)

Look up the values in Appendix E Standard reduction potential for Zn²⁺(aq): \(-0.76 \ \mathrm{V}\) Standard reduction potential for Cd²⁺(aq): \(-0.40 \ \mathrm{V}\) Since Cd²⁺(aq) has a higher reduction potential, it is the stronger oxidizing agent.

Step 5: (c) Cl⁻(aq) or ClO₃⁻(aq)

Look up the values in Appendix E Standard reduction potential for Cl⁻(aq): \(-1.36 \ \mathrm{V}\) Standard reduction potential for ClO₃⁻(aq): \(+1.47 \ \mathrm{V}\) Since ClO₃⁻(aq) has a higher reduction potential, it is the stronger oxidizing agent.

Step 6: (d) H₂O₂(aq) or O₃(g)

Look up the values in Appendix E Standard reduction potential for H₂O₂(aq): \(+0.68 \ \mathrm{V}\) Standard reduction potential for O₃(g): \(+2.07 \ \mathrm{V}\) Since O₃(g) has a higher reduction potential, it is the stronger oxidizing agent.