Which of the following is / are correctly matched ?

Options

A. `{:("Column-I(Metals)","Calumn-II(Process used for extraction)"),("Titanium","Kroll process"):}`
B. `{:("Column-I(Metals)","Calumn-II(Process used for extraction)"),("Aluminium","Baeyer process"):}`
C. `{:("Column-I(Metals)","Calumn-II(Process used for extraction)"),("Chromium","Thermite process"):}`
D. `{:("Column-I(Metals)","Calumn-II(Process used for extraction)"),("Silver","Mac-Arthur cyanide process"):}`

Answer

To determine which of the given metal-extraction process pairs are correctly matched, we will analyze each pair step by step.

### Step-by-Step Solution:

1. **Titanium - Kroll Process**:
- The Kroll process is indeed used for the extraction of titanium. It involves the reduction of titanium tetrachloride (TiCl4) using magnesium at high temperatures (around 800°C).
- **Reaction**:
\[ \text{TiCl}_4 + 2\text{Mg} \rightarrow \text{Ti} + 2\text{MgCl}_2 \]
- **Conclusion**: This pair is correctly matched.

2. **Aluminium - Bayer Process**:
- The Bayer process is used for refining bauxite to produce alumina (Al2O3), which is then used to extract aluminum via electrolysis.
- However, the extraction of aluminum itself is done through the Hall-Héroult process, not the Bayer process.
- **Conclusion**: This pair is incorrectly matched.

3. **Chromium - Thermite Process**:
- The thermite process involves the reduction of metal oxides using aluminum as a reducing agent. It is indeed used for extracting chromium from its oxide.
- **Reaction**:
\[ \text{Cr}_2\text{O}_3 + 2\text{Al} \rightarrow 2\text{Cr} + \text{Al}_2\text{O}_3 \]
- **Conclusion**: This pair is correctly matched.

4. **Silver - MacArthur-Forrest (Cyanide) Process**:
- The MacArthur-Forrest process, also known as the cyanide process, is used for extracting silver (and gold) from ores by dissolving them in a dilute solution of sodium cyanide or potassium cyanide.
- **Conclusion**: This pair is correctly matched.

### Summary of Matches:
- **Correctly Matched**:
- 1. Titanium - Kroll Process
- 3. Chromium - Thermite Process
- 4. Silver - MacArthur-Forrest Process

- **Incorrectly Matched**:
- 2. Aluminium - Bayer Process

### Final Answer:
The pairs that are correctly matched are:
- Titanium with Kroll Process
- Chromium with Thermite Process
- Silver with MacArthur-Forrest Process