In which of the following minerals, `Al` is present ?
1. Fluorspar
2. Mica
3. Feldspar
4. Cryolite

Options

A. 1, 2, 3
B. 1, 2, 4
C. 2, 3, 4
D. 1, 2, 3, 4

Answer

To determine in which of the given minerals aluminum (Al) is present, we will analyze the molecular formulas of each mineral listed in the question.

1. **Fluorspar**: The chemical formula for fluorspar is CaF₂ (calcium fluoride). This mineral does not contain aluminum.

2. **Mica**: The chemical formula for mica is KAl₃Si₃O₁₀(OH)₂. This formula indicates the presence of aluminum (Al) in the structure of mica.

3. **Feldspar**: The chemical formula for feldspar can vary, but a common one is K₂O·Al₂O₃·6SiO₂. This formula shows that feldspar contains aluminum (Al).

4. **Cryolite**: The chemical formula for cryolite is Na₃AlF₆. This formula also indicates the presence of aluminum (Al).

Now, summarizing the findings:
- **Fluorspar**: No Al
- **Mica**: Contains Al
- **Feldspar**: Contains Al
- **Cryolite**: Contains Al

Thus, the minerals that contain aluminum are **Mica, Feldspar, and Cryolite**.

**Final Answer**: 2 (Mica), 3 (Feldspar), and 4 (Cryolite) contain aluminum.