Calcination is the process in which

Options

A. Heating the are in presence of air
B. Heating the one in absence of air
C. Heating in vacuum
D. Heating of are in presence of `N_2`

Answer

**Step-by-Step Solution:**

1. **Understanding Calcination**: Calcination is a thermal treatment process used to convert an ore into its oxide form. This process is typically applied to metal ores.

2. **Conditions of Calcination**: The key aspect of calcination is that it involves heating the ore. This heating can occur in two specific environments:
- In the presence of limited air (oxygen).
- In the absence of air (in a vacuum).

3. **Purpose of Calcination**: The main goal of calcination is to remove volatile substances such as water or carbon dioxide from the ore. This is particularly relevant for ores that are hydroxides or carbonates.

4. **Chemical Reactions**: During calcination, specific chemical reactions occur. For example, when zinc carbonate (ZnCO₃) is heated, it decomposes into zinc oxide (ZnO) and carbon dioxide (CO₂):
\[ \text{ZnCO}_3 \rightarrow \text{ZnO} + \text{CO}_2 \]

5. **Conclusion**: Based on the definition and characteristics of calcination, the correct answer to the question is that calcination is the process of heating the ore in the absence of air.

**Final Answer**: Calcination is the process in which the ore is heated in the absence of air.

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