25.0 `cm^(3)` of a solution containing 15.0 g of a partially oxidisied sample of green vitrion `(FeSO_(4).7H_(2)O)` per litre required 20.0 `cm^(3)` mL of 0.01 M potassium dichromate solution for oxidiation in aidic medium find out the percentage purity of the given sample of green vitriol

Explanation

To find the percentage purity of the given sample of green vitriol (FeSO₄·7H₂O), we can follow these steps:

### Step 1: Determine the moles of potassium dichromate (K₂Cr₂O₇) used.
Given:
- Volume of K₂Cr₂O₇ solution = 20.0 cm³ = 0.020 L
- Molarity of K₂Cr₂O₇ solution = 0.01 M

Using the formula for moles:
...