The oxidation state of Cr in `CrO_5` is

Options

A. `+4`
B. `+6`
C. `+8`
D. `+10`

Answer

To determine the oxidation state of chromium (Cr) in the compound CrO₅, we can follow these steps:

### Step 1: Understand the structure of CrO₅
CrO₅ is known as chromium oxide peroxide. In this compound, chromium is bonded to one oxygen atom with a double bond and to four oxygen atoms with single bonds, which are part of peroxide groups.

### Step 2: Identify the oxidation states of oxygen
In CrO₅:
- The oxidation state of the oxygen in the double bond (oxide) is -2.
- The oxidation state of the oxygen in the peroxide groups is -1.

### Step 3: Set up the equation for oxidation states
Let the oxidation state of chromium be \( x \). The total contribution to the oxidation state from the four peroxide oxygens is:
- \( 4 \times (-1) = -4 \) (since there are four peroxide oxygens).

The contribution from the one oxide oxygen is:
- \( 1 \times (-2) = -2 \).

### Step 4: Write the equation based on the overall charge
Since CrO₅ is a neutral compound, the sum of the oxidation states must equal 0. Therefore, we can write the equation:
\[ x + (-4) + (-2) = 0 \]

### Step 5: Simplify the equation
This simplifies to:
\[ x - 4 - 2 = 0 \]
\[ x - 6 = 0 \]

### Step 6: Solve for \( x \)
Adding 6 to both sides gives:
\[ x = +6 \]

### Conclusion
The oxidation state of chromium in CrO₅ is +6.

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