Assertion : `CO_(4)^(-)` does not show disproportionation reaction.
Reason : In `ClO_(4)^(-)` , chlorine is present in its highest oxidation state .

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

To solve the assertion and reason question regarding the species \( \text{ClO}_4^{-} \) (chlorate ion), we will analyze both the assertion and the reason step by step.

### Step 1: Determine the oxidation state of chlorine in \( \text{ClO}_4^{-} \)

1. **Identify the oxidation state of oxygen**: The standard oxidation state of oxygen is \(-2\).
2. **Set up the equation**: The overall charge of the ion is \(-1\). Let the oxidation state of chlorine be \(X\).
\[ X + 4(-2) = -1 \]
3. **Solve for \(X\)**:
\[ X - 8 = -1 \implies X = +7 \]
Therefore, the oxidation state of chlorine in \( \text{ClO}_4^{-} \) is \( +7 \).

### Step 2: Analyze the assertion

- **Assertion**: \( \text{ClO}_4^{-} \) does not show disproportionation reaction.
- **Disproportionation reaction**: This is a reaction where a substance is simultaneously oxidized and reduced.
- Since chlorine in \( \text{ClO}_4^{-} \) is in its highest oxidation state (+7), it cannot be oxidized further (it cannot lose more electrons). Thus, it can only be reduced (gain electrons).

### Step 3: Analyze the reason

- **Reason**: In \( \text{ClO}_4^{-} \), chlorine is present in its highest oxidation state.
- This statement is true because the highest oxidation state for chlorine is indeed +7. Therefore, chlorine cannot undergo oxidation in this state.

### Step 4: Conclusion

- Since chlorine in \( \text{ClO}_4^{-} \) cannot be oxidized further, it cannot undergo a disproportionation reaction.
- Both the assertion and the reason are true, and the reason correctly explains the assertion.

### Final Answer

Both the assertion and the reason are true, and the reason is the correct explanation for the assertion.