The chief ore of aluminium is

Options

A. cryolite
B. feldspar
C. kaolin
D. bauxite

Answer

To determine the chief ore of aluminium, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ores**: Ores are naturally occurring rocks or minerals from which metals can be extracted. They contain a significant amount of the metal in a form that can be economically processed.

2. **Identifying the Options**: The question provides four options: cryolite, feldspar, kaolinite, and bauxite. We need to identify which of these is the primary source of aluminium.

3. **Researching Aluminium Ores**: Among the listed options, we need to recall which of these is known to be the chief ore of aluminium.

4. **Identifying Bauxite**: Bauxite is widely recognized as the primary ore of aluminium. It is primarily composed of hydrated aluminium oxides and may also contain iron oxides.

5. **Chemical Composition of Bauxite**: The chemical formula of bauxite is typically represented as Al2O3·2H2O, indicating that it contains aluminium oxide combined with water.

6. **Conclusion**: Based on the information gathered, the chief ore of aluminium is bauxite.

### Final Answer:
The chief ore of aluminium is **bauxite**.

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