Calculate difference between oxidation state of chromium (Cr) in blue and green coloured chromium species formed during the following given transformation.

Answer

To calculate the difference between the oxidation states of chromium (Cr) in the blue and green colored chromium species formed during the transformation, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Blue Colored Chromium Species**:
- The blue colored chromium species is CrO5.

2. **Determine the Oxidation State of Chromium in CrO5**:
- In CrO5, we need to find the oxidation state of chromium (let's denote it as x).
- The formula for CrO5 consists of 4 oxygen atoms with a -1 oxidation state (peroxide) and 1 oxygen atom with a -2 oxidation state.
- Therefore, the equation can be set up as:
\[ x + 4(-1) + (-2) = 0 \]
- Simplifying this gives:
\[ x - 4 - 2 = 0 \implies x = +6 \]
- Thus, the oxidation state of chromium in CrO5 is +6.

3. **Identify the Green Colored Chromium Species**:
- The green colored chromium species is Cr3+.

4. **Determine the Oxidation State of Chromium in Cr3+**:
- The oxidation state of chromium in Cr3+ is simply +3.

5. **Calculate the Difference in Oxidation States**:
- Now, we find the difference between the oxidation states of chromium in CrO5 and Cr3+:
\[ \text{Difference} = \text{Oxidation state in CrO5} - \text{Oxidation state in Cr3+} = +6 - (+3) = +3 \]

### Final Answer:
The difference between the oxidation state of chromium in blue colored CrO5 and green colored Cr3+ is **3**.

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