In which of the following ores at least metal is in `+3` oxidation state and crystal system is orthorhombic

Options

A. Haematite
B. Copper pyrite
C. Diaspore
D. Aragonite

Explanation

To solve the question of identifying which ore has at least one metal in the +3 oxidation state and crystallizes in the orthorhombic system, we will analyze each option provided.

### Step-by-Step Solution:

1. **Analyze Hematite:**
- **Chemical Formula:** Hematite has the formula \( \text{Fe}_2\text{O}_3 \).
- **Oxidation State:** The oxidation state of iron (Fe) in hematite is +3.
- **Crystal System:** Hematite crystallizes in the hexagonal system.
- **Conclusion:** Hematite has +3 oxidation state but does not meet the orthorhombic crystal system requirement.

2. **Analyze Copper Pyrite:**
- **Chemical Formula:** Copper pyrite has the formula \( \text{CuFeS}_2 \).
- **Oxidation States:** The oxidation state of copper (Cu) is +1 and iron (Fe) is +2.
- **Crystal System:** Copper pyrite crystallizes in the tetragonal system.
- **Conclusion:** Copper pyrite does not have any metal in +3 oxidation state and does not meet the orthorhombic requirement.

3. **Analyze Diaspore:**
- **Chemical Formula:** Diaspore has the formula \( \text{AlO(OH)} \).
- **Oxidation State:** The oxidation state of aluminum (Al) is +3.
- **Crystal System:** Diaspore crystallizes in the orthorhombic system.
- **Conclusion:** Diaspore meets both criteria: it has +3 oxidation state and crystallizes in the orthorhombic system.

4. **Analyze Aragonite:**
- **Chemical Formula:** Aragonite has the formula \( \text{CaCO}_3 \).
- **Oxidation State:** The oxidation state of calcium (Ca) is +2.
- **Crystal System:** Aragonite crystallizes in the orthorhombic system.
- **Conclusion:** Aragonite does not have any metal in +3 oxidation state.

### Final Answer:
The only ore that meets both criteria (at least one metal in +3 oxidation state and crystallizes in the orthorhombic system) is **Diaspore**.