Oxidation state exhibited by Cl in `HClO_(4)` is

Explanation

To find the oxidation state of chlorine (Cl) in perchloric acid (HClO₄), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the oxidation states of known elements**:
- In HClO₄, hydrogen (H) has an oxidation state of +1.
- Oxygen (O) typically has an oxidation state of -2.

2. **Set up the equation**:
- Let the oxidation state of chlorine (Cl) be \( x \).
- The formula for perchloric acid is HClO₄, which contains 1 hydrogen atom, 1 chlorine atom, and 4 oxygen atoms.

3. **Write the equation based on the sum of oxidation states**:
- The total oxidation state must equal zero for a neutral compound.
- Therefore, we can write the equation:
\[ (+1) + x + 4(-2) = 0 \]

4. **Simplify the equation**:
- Substitute the oxidation states into the equation:
\[ 1 + x - 8 = 0 \]
- This simplifies to:
\[ x - 7 = 0 \]

5. **Solve for \( x \)**:
- Rearranging gives:
\[ x = +7 \]

6. **Conclusion**:
- The oxidation state of chlorine in HClO₄ is +7.

### Final Answer:
The oxidation state exhibited by Cl in HClO₄ is +7.

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