To determine the oxidation state of chlorine in potassium chlorate (KClO₃), we need to analyze the compound step by step. ### Step 1: Understand the Composition of Potassium Chlorate Potassium chlorate is made up of three elements: potassium (K), chlorine (Cl), and oxygen (O). The chemical formula is KClO₃, which indicates that there is one potassium atom, one chlorine atom, and three oxygen atoms in each molecule of potassium chlorate. ### Step 2: Assign Known Oxidation States 1. **Potassium (K)**: Potassium is an alkali metal and typically has an oxidation state of +1 in its compounds. 2. **Oxygen (O)**: In most compounds, oxygen has an oxidation state of -2. Since there are three oxygen atoms in KClO₃, the total contribution from oxygen is: \[ 3 \text{ O} \times (-2) = -6 \] ### Step 3: Set Up the Equation The sum of the oxidation states in a neutral compound must equal zero. Therefore, we can set up the following equation to find the oxidation state of chlorine (let's denote it as \( x \)): \[ \text{Oxidation state of K} + \text{Oxidation state of Cl} + \text{Total oxidation state of O} = 0 \] Substituting the known values: \[ (+1) + x + (-6) = 0 \] ### Step 4: Solve for the Oxidation State of Chlorine Now, we can simplify the equation: \[ 1 + x - 6 = 0 \] \[ x - 5 = 0 \] \[ x = +5 \] Thus, the oxidation state of chlorine in potassium chlorate (KClO₃) is +5. ### Step 5: Evaluate the Options Now, let's evaluate the provided options: - **A. +1**: This is incorrect because it underestimates the oxidation state of chlorine in this compound. - **B. +2**: This is also incorrect as it does not account for the total oxidation state contributions from oxygen. - **C. +3**: This is incorrect as well; while it is closer than the previous options, it still does not reflect the correct oxidation state. - **D. +5**: This is the correct answer, as we calculated. ### Summary of the Correct Answer The correct option is **D. +5**. ### Revision Summary - The oxidation state of potassium (K) is +1, and that of oxygen (O) is -2. - In KClO₃, the total contribution from three oxygen atoms is -6. - The equation for the oxidation states leads to the conclusion that chlorine has an oxidation state of +5. - Always remember to check the sum of oxidation states in a neutral compound to ensure it equals zero.