Oxidation states of the metal in the minerals haematite and magnetite, respectively, are

Options

A. `II,III` in haematite and III in magnetite
B. `II,III` in heamatite and II in magnitite
C. `II` in haematite and `II,III` in magnetite
D. `III` is haematite and `II, III` in magnetite

Explanation

To determine the oxidation states of the metal in the minerals haematite and magnetite, we will follow these steps:

### Step 1: Identify the formulas of the minerals
- Haematite: The formula is \( \text{Fe}_2\text{O}_3 \).
- Magnetite: The formula is \( \text{Fe}_3\text{O}_4 \).

### Step 2: Calculate the oxidation state of iron in haematite
1. Write the formula: \( \text{Fe}_2\text{O}_3 \).
2. Let the oxidation state of iron (Fe) be \( x \).
3. The oxidation state of oxygen (O) is \( -2 \).
4. Set up the equation based on the neutrality of the compound:
\[ 2x + 3(-2) = 0 \]
5. Simplify the equation:
\[ 2x - 6 = 0 \]
6. Solve for \( x \):
\[ 2x = 6 \implies x = 3 \]

### Step 3: Calculate the oxidation state of iron in magnetite
1. Write the formula: \( \text{Fe}_3\text{O}_4 \).
2. This can be considered as a combination of \( \text{Fe}_2\text{O}_3 \) and \( \text{FeO} \).
3. Let the oxidation state of iron in magnetite be \( x \).
4. Set up the equation:
\[ 3x + 4(-2) = 0 \]
5. Simplify the equation:
\[ 3x - 8 = 0 \]
6. Solve for \( x \):
\[ 3x = 8 \implies x = \frac{8}{3} \text{ (for the total of Fe in magnetite)} \]
- However, we can also analyze it as \( \text{Fe}_2\text{O}_3 \) (where Fe is +3) and \( \text{FeO} \) (where Fe is +2).

### Step 4: Summary of oxidation states
- In haematite (\( \text{Fe}_2\text{O}_3 \)), the oxidation state of Fe is \( +3 \).
- In magnetite (\( \text{Fe}_3\text{O}_4 \)), the oxidation states of Fe are \( +2 \) and \( +3 \).

### Final Answer
- The oxidation states of the metal in haematite and magnetite, respectively, are \( +3 \) and a mixture of \( +2 \) and \( +3 \).