Determine the standard reduction potential (E°red) for the reduction of Tl³⁺(aq) to Tl⁺(aq).

• A. +0.75 V
• B. -0.50 V
• C. +1.25 V
• D. +0.15 V

Answer: (D)

Verified step by step guidance

1. Understand that the standard reduction potential (E°red) is a measure of the tendency of a chemical species to be reduced, and it is expressed in volts (V).
2. Identify the given reduction potentials for the reduction of Tl³⁺(aq) to Tl⁺(aq). These are: +0.75 V, -0.50 V, and +1.25 V.
3. Recognize that the standard reduction potential for a half-reaction can be determined by considering the standard reduction potentials of related half-reactions and using the principle of adding potentials for sequential reactions.
4. Consider the possibility that the given potentials might represent different steps or related reactions in the reduction process. For example, Tl³⁺(aq) might first be reduced to Tl²⁺(aq) and then to Tl⁺(aq).
5. Use the concept of standard reduction potentials and the given values to deduce the correct potential for the overall reduction of Tl³⁺(aq) to Tl⁺(aq), ensuring that the sum of potentials for any intermediate steps matches the given correct answer of +0.15 V.