Which of the following reactions does not occur during calcination?

Options

A. `CaCO_(3)rarrCaO+CO_(2)`
B. `CuCo_(3).Cu(OH)_(2)rarr2CuO+H_(2)Odarr+CO_(2)darr`
C. `CuS+O_(2)rarrCuO+SO_(2)darr`
D. `CuSO_(4).5H_(2)OrarrCuSO_(4)+5H_(2)Odarr`

Explanation

To determine which reaction does not occur during calcination, we first need to understand what calcination is. Calcination is the process of heating a substance to a high temperature in the absence or limited supply of air. This process is typically used to drive off volatile substances, such as water or carbon dioxide, or to induce thermal decomposition.

Now, let's analyze each of the given reactions:

1. **Reaction 1: CaCO3 → CaO + CO2**
- This reaction involves the thermal decomposition of calcium carbonate (CaCO3) into calcium oxide (CaO) and carbon dioxide (CO2). This reaction occurs during calcination as it takes place in the absence of air.

2. **Reaction 2: CuCO3·Cu(OH)2 → 2CuO + H2O + CO2**
- This reaction involves the decomposition of copper carbonate hydroxide into copper oxide, water, and carbon dioxide. Similar to the first reaction, this also occurs during calcination as it happens in limited air supply.

3. **Reaction 3: CuS + O2 → CuO + SO2**
- In this reaction, copper sulfide (CuS) reacts with oxygen (O2) to produce copper oxide (CuO) and sulfur dioxide (SO2). Since this reaction requires the presence of oxygen, it does not occur during calcination, which specifically requires the absence or limited supply of air.

4. **Reaction 4: CuSO4·5H2O → CuSO4 + 5H2O**
- This reaction involves the removal of water of crystallization from copper sulfate pentahydrate. This process can occur during calcination as it involves heating to remove water.

Based on the analysis, the reaction that does not occur during calcination is:

**Answer: Reaction 3 (CuS + O2 → CuO + SO2)**