Find the oxidation number of `Cl` in `HCl, HClO

Explanation

To find the oxidation number of chlorine (Cl) in the compounds HCl and HClO, we can follow these steps:

### Step 1: Determine the oxidation number of Cl in HCl
1. **Identify the oxidation states of other elements in HCl**:
- Hydrogen (H) has an oxidation number of +1.
- The compound HCl is neutral, so the sum of oxidation numbers must equal 0.

2. **Set up the equation**:
- Let the oxidation number of Cl be \( x \).
- The equation can be written as:
\[ x + (+1) = 0 \]

3. **Solve for x**:
- Rearranging the equation gives:
\[ x = -1 \]
- Therefore, the oxidation number of Cl in HCl is **-1**.

### Step 2: Determine the oxidation number of Cl in HClO
1. **Identify the oxidation states of other elements in HClO**:
- Hydrogen (H) has an oxidation number of +1.
- Oxygen (O) has an oxidation number of -2.
- The compound HClO is also neutral, so the sum of oxidation numbers must equal 0.

2. **Set up the equation**:
- Let the oxidation number of Cl be \( x \).
- The equation can be written as:
\[ x + (+1) + (-2) = 0 \]

3. **Solve for x**:
- Rearranging the equation gives:
\[ x - 1 = 0 \implies x = +1 \]
- Therefore, the oxidation number of Cl in HClO is **+1**.

### Final Results:
- The oxidation number of Cl in HCl is **-1**.
- The oxidation number of Cl in HClO is **+1**.