Direction this section contains Assertion and Reason type question each question has 4 choice (1)(2)(3)(4) out of only which one is correct
(1) Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion (2)Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion (3)Assertion is correct but Reason is incorrect (4) Both Assertion and Reason are incorrect
Assertion(A): Oxidation number of Chromium in `CrO_5` is `+6`
Reason(R):Oxidation number of each oxygen atoms in `CrO_5` is `-1.5`

Options

A. Both assertion and reason are correct and reason is the correct explanation of the assertion
B. Both assertion and reason are correct but reason is not the correct explantion
C. Assertion is correct but reason is incorrect
D. Both assertion and reason are incorrect

Answer

To solve the assertion and reason question regarding the oxidation numbers in `CrO_5`, we will analyze both the assertion and the reason step by step.

### Step 1: Determine the Oxidation Number of Chromium in `CrO_5`

1. **Understanding the Compound**: `CrO_5` is a compound that contains chromium (Cr) and oxygen (O). It is important to analyze the structure of `CrO_5` to determine the oxidation states.

2. **Identifying the Structure**: `CrO_5` contains peroxy linkages (O-O bonds) which affect the oxidation states of the oxygen atoms. In `CrO_5`, there are four oxygen atoms involved in peroxy linkages and one oxygen atom that is in the usual oxide state.

3. **Assigning Oxidation States**:
- The oxidation number of the usual oxide oxygen (O) is `-2`.
- The peroxy oxygen (O-O) has an oxidation number of `-1` for each oxygen atom.
- Therefore, in `CrO_5`, we have 4 oxygen atoms contributing `-1` each (total of `-4`) and 1 oxygen contributing `-2`.

4. **Setting Up the Equation**:
- Let the oxidation number of chromium be `x`.
- The total oxidation state equation can be set up as:
\[ x + 4(-1) + (-2) = 0 \]
- Simplifying gives:
\[ x - 4 - 2 = 0 \implies x - 6 = 0 \implies x = +6 \]

### Step 2: Determine the Oxidation Number of Oxygen in `CrO_5`

1. **Calculating the Oxidation Number of Oxygen**:
- As derived earlier, the four peroxy oxygen atoms have an oxidation number of `-1` each, leading to an average oxidation number of `-1.5` for the oxygen atoms in `CrO_5`.

### Conclusion

- **Assertion (A)**: The oxidation number of Chromium in `CrO_5` is `+6` (This is correct).
- **Reason (R)**: The oxidation number of each oxygen atom in `CrO_5` is `-1.5` (This is also correct).

### Final Evaluation
- Since both the assertion and reason are correct, but the reason does not explain the assertion directly, the correct choice is:
**(2) Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.**

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