What is the oxidation number of Cr in `CrO_2Cl_2` ?

Answer

To find the oxidation number of chromium (Cr) in the compound CrO₂Cl₂, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the oxidation states of the other elements in the compound:**
- Oxygen (O) typically has an oxidation state of -2.
- Chlorine (Cl) typically has an oxidation state of -1.

2. **Set up the equation using the oxidation states:**
- Let the oxidation number of chromium (Cr) be represented as \( X \).
- In the compound CrO₂Cl₂, there are 2 oxygen atoms and 2 chlorine atoms.
- The total contribution from the oxygen atoms is \( 2 \times (-2) = -4 \).
- The total contribution from the chlorine atoms is \( 2 \times (-1) = -2 \).

3. **Write the equation based on the sum of oxidation states:**
- Since CrO₂Cl₂ is a neutral compound, the sum of the oxidation states must equal 0.
- Therefore, we can write the equation:
\[ X + (-4) + (-2) = 0 \]

4. **Simplify the equation:**
- Combine the constants:
\[ X - 4 - 2 = 0 \]
\[ X - 6 = 0 \]

5. **Solve for \( X \):**
- Rearranging gives:
\[ X = 6 \]

### Conclusion:
The oxidation number of chromium (Cr) in CrO₂Cl₂ is +6.

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