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, follow these steps:

### Step 1: Identify the blue colored chromium species
The blue colored chromium species is CrO5, which is formed from the reaction of CrO4^2- in acidic medium with H2O2.

### Step 2: Calculate the oxidation state of chromium in CrO4^2-
For CrO4^2-, we can set up the equation for the oxidation state (X) of chromium:
\[ X + 4(-2) = -2 \]
\[ X - 8 = -2 \]
\[ X = +6 \]
Thus, the oxidation state of chromium in CrO4^2- is +6.

### Step 3: Calculate the oxidation state of chromium in CrO5
In CrO5, the structure can be represented as CrO4 with an additional oxygen. The oxidation states of the oxygen atoms in CrO5 are -1 (for the four oxygens) and -2 (for the double-bonded oxygen):
- The four oxygens contribute: 4(-1) = -4
- The double-bonded oxygen contributes: -2

Setting up the equation for the oxidation state of chromium (Y):
\[ Y + (-4) + (-2) = 0 \]
\[ Y - 6 = 0 \]
\[ Y = +6 \]
Thus, the oxidation state of chromium in CrO5 is also +6.

### Step 4: Identify the green colored chromium species
The green colored chromium species is Cr^3+, which is formed from the reaction of Cr2O3 in acidic medium.

### Step 5: Calculate the oxidation state of chromium in Cr^3+
In Cr^3+, the oxidation state of chromium is simply +3.

### Step 6: Calculate the difference in oxidation states
Now, we can find the difference in oxidation states between the blue (CrO5) and green (Cr^3+) colored species:
\[ \text{Difference} = \text{Oxidation state of Cr in CrO5} - \text{Oxidation state of Cr in Cr}^3+ \]
\[ \text{Difference} = +6 - (+3) \]
\[ \text{Difference} = +6 - 3 = 3 \]

### Final Answer
The difference between the oxidation states of chromium in the blue and green colored species is **3**.

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