Assertion : `CuSO_(4).5H_(2)O` on heating to `250^(@)C` losses all the five `H_(2) O` molecules and becomes anhydrous.
Reason : All five `H_(2) O` molecules are coordinated to the central `Cu^(2+)` ion.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the question, we need to evaluate both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that `CuSO4.5H2O` (copper(II) sulfate pentahydrate) loses all five water molecules when heated to `250°C` and becomes anhydrous.
- On heating, copper(II) sulfate pentahydrate does indeed lose its water of crystallization. The process can be represented as:
\[ \text{CuSO}_4 \cdot 5\text{H}_2\text{O} \xrightarrow{250^\circ C} \text{CuSO}_4 + 5\text{H}_2\text{O} \]
- Therefore, the assertion is **correct**.

2. **Understanding the Reason**:
- The reason states that all five water molecules are coordinated to the central `Cu^(2+)` ion.
- In reality, only four of the five water molecules are coordinated to the `Cu^(2+)` ion in the structure of copper(II) sulfate pentahydrate. The fifth water molecule is involved in hydrogen bonding and is not directly coordinated.
- Therefore, the reason is **incorrect**.

3. **Conclusion**:
- Since the assertion is true and the reason is false, the correct answer is that the assertion is true, but the reason is false.

### Final Answer:
- The assertion is true, and the reason is false.