Which of the following species has the highest oxidizing power based on their oxidation numbers?

• A. ClO3-
• B. Cl-
• C. ClO2
• D. Cl2

Answer: (D)

Verified step by step guidance

1. Step 1: Understand that oxidizing power refers to the ability of a species to gain electrons (i.e., to be reduced). The stronger the oxidizing agent, the more positive (or higher) its reduction potential and the higher its oxidation state tends to be before reduction.
2. Step 2: Determine the oxidation number of chlorine in each species to compare their relative oxidizing abilities. Use the general rules for oxidation numbers: oxygen is usually -2, and the overall charge of the ion or molecule must be considered.
3. Step 3: Calculate the oxidation number of chlorine in each species: - For ClO3⁻: Let the oxidation number of Cl be x. Oxygen is -2, and there are 3 oxygens, so total oxygen charge is -6. The overall charge is -1. Set up the equation: x + 3(-2) = -1, which simplifies to x - 6 = -1.
4. Step 4: Repeat the calculation for ClO2 (neutral molecule): Let the oxidation number of Cl be y. Oxygen is -2, and there are 2 oxygens, so total oxygen charge is -4. Set up the equation: y + 2(-2) = 0, which simplifies to y - 4 = 0.
5. Step 5: For Cl⁻, the oxidation number of Cl is simply -1 because it is a monatomic ion with a -1 charge. After finding these oxidation numbers, compare them to understand which species has chlorine in the highest oxidation state, indicating the strongest oxidizing power. Note that Cl2 (elemental chlorine) has an oxidation number of 0, and its oxidizing power can be compared accordingly.