Which of the following substance will leave a black residue on strong heating?

Options

A. `CuSO_(4)*5H_(2)O`
B. `ZnCO_(3)`
C. `PbCO_(3)`
D. `MnSO_(4)`

Answer

To determine which of the given substances will leave a black residue upon strong heating, we will analyze each substance one by one based on their thermal decomposition reactions.

### Step-by-Step Solution:

1. **Analyze Copper Sulfate Pentahydrate (CuSO4·5H2O)**:
- When heated, copper sulfate pentahydrate loses its water molecules first, forming anhydrous copper sulfate (CuSO4).
- Further heating of anhydrous copper sulfate leads to the formation of copper(II) oxide (CuO) and sulfur trioxide (SO3) gas.
- Copper(II) oxide is black in color.
- **Conclusion**: Copper sulfate pentahydrate leaves a black residue upon strong heating.

2. **Analyze Zinc Carbonate (ZnCO3)**:
- Upon strong heating, zinc carbonate decomposes into zinc oxide (ZnO) and carbon dioxide (CO2) gas.
- Zinc oxide is white when cold and yellow when hot, but it does not produce a black residue.
- **Conclusion**: Zinc carbonate does not leave a black residue upon strong heating.

3. **Analyze Lead Carbonate (PbCO3)**:
- When heated, lead carbonate decomposes into lead(II) oxide (PbO) and carbon dioxide (CO2) gas.
- Lead(II) oxide is orange in color, and further heating can produce lead(IV) oxide (PbO2), which is red.
- **Conclusion**: Lead carbonate does not leave a black residue upon strong heating.

4. **Analyze Manganese Sulfate (MnSO4)**:
- Upon strong heating, manganese sulfate decomposes into manganese(II) oxide (MnO) and sulfur dioxide (SO2) and sulfur trioxide (SO3) gases.
- Manganese(II) oxide is black in color.
- **Conclusion**: Manganese sulfate leaves a black residue upon strong heating.

### Final Answer:
The substances that will leave a black residue upon strong heating are:
- Copper sulfate pentahydrate (CuSO4·5H2O)
- Manganese sulfate (MnSO4)