Oxidation state of oxygen in `CrO_(5)` is

Options

A. -1
B. -2
C. Both (1) & (2)
D. `-1/2`

Answer

To determine the oxidation state of oxygen in the compound \( \text{CrO}_5 \), we need to analyze the structure of the compound and the bonding present.

### Step 1: Understand the structure of \( \text{CrO}_5 \)
- The compound \( \text{CrO}_5 \) consists of one chromium (Cr) atom and five oxygen (O) atoms.
- In this compound, there are peroxide linkages, which means that some of the oxygen atoms are bonded in a way that changes their typical oxidation state.

### Step 2: Identify the types of oxygen in \( \text{CrO}_5 \)
- In \( \text{CrO}_5 \), there are two types of oxygen:
1. **Oxygen in peroxide linkages**: These oxygen atoms typically have an oxidation state of -1.
2. **Oxygen double-bonded to chromium**: This oxygen atom has an oxidation state of -2.

### Step 3: Count the number of each type of oxygen
- In \( \text{CrO}_5 \):
- There are 4 oxygen atoms in the form of peroxides (each with an oxidation state of -1).
- There is 1 oxygen atom double-bonded to chromium (with an oxidation state of -2).

### Step 4: Calculate the overall oxidation state
- The total contribution of the oxidation states from the oxygen atoms can be calculated as follows:
- Contribution from 4 peroxide oxygens: \( 4 \times (-1) = -4 \)
- Contribution from 1 double-bonded oxygen: \( 1 \times (-2) = -2 \)
- Therefore, the total oxidation state from oxygen is \( -4 + (-2) = -6 \).

### Step 5: Determine the oxidation state of chromium
- Let the oxidation state of chromium be \( x \).
- The overall charge of the compound \( \text{CrO}_5 \) is neutral (0), so we can set up the equation:
\[ x + (-6) = 0 \]
\[ x = +6 \]

### Conclusion
- The oxidation states of oxygen in \( \text{CrO}_5 \) are:
- **-1** for the four oxygen atoms in peroxide linkages.
- **-2** for the one oxygen atom double-bonded to chromium.
- Therefore, the answer is that the oxidation state of oxygen in \( \text{CrO}_5 \) is both -1 and -2.

### Final Answer
The oxidation state of oxygen in \( \text{CrO}_5 \) is both -1 and -2 (Option C).

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