How many water molecules in blue vitriol are coordinated to the metal ?

Options

A. 3,2
B. 2,3
C. 4,1
D. `5.0`

Answer

To determine how many water molecules in blue vitriol are coordinated to the metal, we can follow these steps:

### Step 1: Understand what blue vitriol is
Blue vitriol is the common name for copper(II) sulfate pentahydrate, which has the chemical formula CuSO₄·5H₂O.

### Step 2: Analyze the formula
The formula indicates that there are five water molecules (5H₂O) associated with each formula unit of copper(II) sulfate.

### Step 3: Identify the coordination of water molecules
In the structure of blue vitriol, four of these water molecules are directly coordinated to the copper ion (Cu²⁺). This means they are bonded directly to the metal ion.

### Step 4: Determine the role of the fifth water molecule
The fifth water molecule is not directly coordinated to the copper ion. Instead, it is involved in hydrogen bonding with the sulfate ions (SO₄²⁻) in the crystal lattice.

### Step 5: Conclusion
Thus, the total number of water molecules that are coordinated to the metal (copper ion) in blue vitriol is **4**.

### Final Answer
4 water molecules are coordinated to the metal in blue vitriol (CuSO₄·5H₂O).

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