Metals occur in nature in the free as well as in the combined state. The less reactive metals are generally found in the free state. Most of the metals, however are found in the combined form as minerals. The minerals from which metals can be obtained on a commercial scale are called ores. In other words, the minerals from which metals can be extracted profitably are called ores. Thus, bauxite `(Al_(2)O_(3)*2H_(2)O)`and clay `(Al_(2)O_(3).2SiO_(2).2H_(2)O)` are minerals of aluminium. However, it is bauxite that is chiefly used to obtain aluminium commercially. So, bauxite, and not clay, is an ore of aluminium.
Which of the following is a sulphide ore ?

Options

A. Galena
B. Cryolite
C. Cuprite
D. Bauxite

Explanation

To determine which of the given options is a sulphide ore, we need to understand what sulphide ores are and identify them among the options provided.

### Step-by-Step Solution:

1. **Understand the Definition of Ores**:
- Ores are naturally occurring minerals from which metals can be extracted profitably.

2. **Identify Sulphide Ores**:
- Sulphide ores are minerals that contain metal combined with sulfur. The general formula for sulphide ores is \( \text{MX} \), where \( \text{M} \) is the metal and \( \text{X} \) is sulfur.

3. **List Common Sulphide Ores**:
- Some common examples of sulphide ores include:
- Galena (PbS) - Lead sulphide
- Chalcopyrite (CuFeS2) - Copper iron sulphide
- Sphalerite (ZnS) - Zinc sulphide

4. **Evaluate the Given Options**:
- From the video transcript, the options mentioned are:
- Galena (PbS)
- Cryolite (Na3AlF6)
- Cuprite (Cu2O)
- Bauxite (Al2O3·2H2O)

5. **Identify the Sulphide Ore**:
- Among the options, Galena (PbS) is the only mineral that contains sulfur combined with lead, making it a sulphide ore.

### Conclusion:
- The sulphide ore from the given options is **Galena (PbS)**.