Final answer:
The more positive the reduction potential, the more the substance on the right "wants" to be oxidized.
Step-by-step explanation:
The blank in the statement should be filled with the word 'positive.' The more positive the reduction potential, the more the substance on the right "wants" to be oxidized. This is because a larger reduction potential signifies that a substance is easier to reduce, and thus, more likely to gain electrons during a chemical reaction.
For example, permanganate with a large reduction potential, is considered a strong oxidizing agent, meaning it readily gains electrons and causes other substances to lose electrons (be oxidized).
Similarly, comparing the standard electrode potentials, oxidizing strength decreases with more negative reduction potentials. Thus, a substance with a high positive reduction potential tends to be an excellent oxidizer, easily reduced itself by accepting electrons from other substances. This is a fundamental concept in electrochemistry that helps predict the spontaneity of redox reactions.