White vitriol is

Options

A. `CuSO_4.5H_2O`
B. `FeSO_4.7H_2O`
C. `ZnSO_4.7H_2O`
D. `NiSO_4.5H_2O`

Answer

**Step-by-Step Solution:**

1. **Understanding the Term "White Vitriol":**
- White vitriol is a common name used for a specific chemical compound. It is important to identify what this compound is.

2. **Identifying the Chemical Compound:**
- The chemical name for white vitriol is zinc sulfate. The full chemical formula for white vitriol is zinc sulfate heptahydrate, which is represented as ZnSO₄·7H₂O.

3. **Formation of White Vitriol:**
- White vitriol can be formed by heating zinc in the presence of a sulfate solution. This reaction occurs in the presence of air, leading to the formation of zinc sulfate.

4. **Characteristics of White Vitriol:**
- The crystals of white vitriol are white in color, which is why it is referred to as "white vitriol." The heptahydrate form indicates that there are seven water molecules associated with each zinc sulfate molecule.

5. **Uses of White Vitriol:**
- White vitriol has various applications, including its use in the preservation of wood and in the electroplating process for zinc deposition.

6. **Comparison with Other Vitriols:**
- It is also useful to know that other sulfate compounds, such as iron(II) sulfate (FeSO₄), nickel(II) sulfate (NiSO₄), and copper(II) sulfate (CuSO₄), are known as vitriols but have different colors (e.g., FeSO₄ is green, NiSO₄ is blue-green, and CuSO₄ is blue).

7. **Conclusion:**
- Therefore, the correct identification of white vitriol is zinc sulfate heptahydrate (ZnSO₄·7H₂O).

**Final Answer:**
White vitriol is zinc sulfate heptahydrate (ZnSO₄·7H₂O).

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