Determine the oxidation number for the indicated element in each of the following substances: e. Cl in HClO2

Verified step by step guidance

1. Identify the oxidation number of hydrogen (H), which is typically +1.
2. Identify the oxidation number of oxygen (O), which is typically -2.
3. Let the oxidation number of chlorine (Cl) be x.
4. Set up the equation based on the sum of oxidation numbers in the compound HClO2, which must equal zero: 1 (for H) + x (for Cl) + 2(-2) (for O) = 0.
5. Solve the equation for x to find the oxidation number of Cl.

Key Concepts

Oxidation Number

The oxidation number, or oxidation state, is a theoretical charge assigned to an atom in a compound, reflecting its degree of oxidation or reduction. It helps in understanding electron transfer in redox reactions. Oxidation numbers can be positive, negative, or zero, and they follow specific rules, such as the oxidation number of oxygen is usually -2, and hydrogen is +1.

Rules for Assigning Oxidation Numbers

There are several rules for assigning oxidation numbers, including that the sum of oxidation numbers in a neutral compound must equal zero. For polyatomic ions, the sum must equal the ion's charge. Additionally, elements in their elemental form have an oxidation number of zero, while alkali metals are always +1 in compounds, and alkaline earth metals are +2.

Structure of HClO2

HClO2, known as chlorous acid, contains chlorine (Cl) bonded to two oxygen atoms and one hydrogen atom. Understanding the molecular structure is crucial for determining the oxidation state of chlorine. In this compound, the presence of oxygen, which typically has a -2 oxidation state, influences the oxidation number of chlorine, requiring careful calculation based on the overall charge balance.