Which of the following set of elements mostly occur as sulphide ores.

Options

A. Zn, Cu, Na
B. Zn, Cu, Pb
C. Fe, Al
D. Cu, Ag, Au

Answer

To determine which set of elements mostly occurs as sulfide ores, we will analyze each option provided:

### Step 1: Analyze Option A (Zn, Cu, Na)
- **Zinc (Zn)**: Occurs as a sulfide ore known as zinc blende (ZnS).
- **Copper (Cu)**: Occurs as a sulfide ore known as chalcocite (Cu2S).
- **Sodium (Na)**: Does not occur as a sulfide ore; it is primarily found in the form of sodium chloride (NaCl).

**Conclusion for Option A**: Not all elements in this option are sulfide ores (Na is not), so this option is incorrect.

### Step 2: Analyze Option B (Zn, Cu, Pb)
- **Zinc (Zn)**: As mentioned, occurs as zinc blende (ZnS).
- **Copper (Cu)**: Occurs as chalcocite (Cu2S).
- **Lead (Pb)**: Occurs as galena (PbS).

**Conclusion for Option B**: All three elements (Zn, Cu, Pb) occur as sulfide ores. This option is correct.

### Step 3: Analyze Option C (Fe, Al)
- **Iron (Fe)**: Typically occurs as iron oxides (e.g., hematite, Fe2O3) rather than sulfide ores.
- **Aluminum (Al)**: Primarily found in the form of oxides (e.g., bauxite) and does not occur as a sulfide ore.

**Conclusion for Option C**: Neither element occurs as sulfide ores, so this option is incorrect.

### Step 4: Analyze Option D (Cu, Ag, Au)
- **Copper (Cu)**: As previously noted, occurs as chalcocite (Cu2S).
- **Silver (Ag)**: Typically found in native form or as silver sulfide (Ag2S), but it is not predominantly a sulfide ore.
- **Gold (Au)**: Often occurs in its native state and does not typically form sulfide ores.

**Conclusion for Option D**: Not all elements in this option are sulfide ores (Ag and Au are not predominantly sulfide ores), so this option is incorrect.

### Final Answer
The correct option is **B (Zn, Cu, Pb)**, as all these elements mostly occur as sulfide ores.

---