Question

half-reaction | e° (v)
a⁺ + e⁻→ a | -0.5
b⁺ + e⁻ → b | 0.0
c⁺ + e⁻→ c | +1.0
which substance acts as the standard in this data set?
substance b
substance c
substance a
they are all equally likely to be reduced.

Explanation:

In standard reduction potential (E°) tables, the standard hydrogen electrode (SHE) is set at 0.0 V, but here, the half - reaction for \(B^{+}+e^{-}\to B\) has an \(E^{\circ}\) of 0.0 V. Substances with \(E^{\circ}\) values are compared relative to a standard, and here the one with \(E^{\circ}=0.0\) (substance B's half - reaction) is the reference standard in this data set. Substance C has a positive \(E^{\circ}\), meaning it is a stronger oxidizing agent than the standard, and substance A has a negative \(E^{\circ}\), meaning it is a stronger reducing agent than the standard. Also, the likelihood of reduction depends on \(E^{\circ}\) (higher \(E^{\circ}\) means more likely to be reduced), so they are not equally likely.

Answer:

A. Substance B