An element 'X, forms compounds of the formula `XCl_(3),X_(2)O_(5)& Ca_(3)X^(2)` but does not form `XCl_(5)`, which of the following is the elements (X) :-

Options

A. N
B. Cl
C. Xe
D. S

Answer

To solve the problem, we need to analyze the given information about the element 'X' and the compounds it forms.

### Step-by-Step Solution:

1. **Identify the Compounds Formed by Element 'X':**
- The element 'X' forms the following compounds:
- \(XCl_3\)
- \(X_2O_5\)
- \(Ca_3X^2\)

2. **Analyze the Compounds:**
- The compound \(XCl_3\) indicates that 'X' can form a trivalent compound with chlorine.
- The compound \(X_2O_5\) suggests that 'X' can exhibit a higher oxidation state, possibly +5.
- The compound \(Ca_3X^2\) indicates that 'X' can form a divalent compound with calcium.

3. **Check the Non-formation of \(XCl_5\):**
- The problem states that 'X' does not form \(XCl_5\). This suggests that 'X' cannot expand its valency beyond three.

4. **Evaluate the Options:**
- **Nitrogen (N):**
- Forms \(NCl_3\), \(N_2O_5\), and \(Ca_3N_2\).
- Cannot form \(NCl_5\) due to the absence of d-orbitals and its inability to expand its covalency beyond three.
- **Fluorine (F):**
- Forms \(FCl_3\) but does not form \(F_2O_5\) or \(Ca_3F^2\) in the same manner.
- **Xenon (Xe):**
- Forms \(XeCl_2\) and \(XeO_3\) but does not fit the criteria for the other compounds.
- **Sulfur (S):**
- Can form \(SCl_2\), \(S_2O_5\), and \(Ca_3S^2\) but can also form \(SCl_6\), which contradicts the requirement.

5. **Conclusion:**
- The only element that fits all the criteria is **Nitrogen (N)**. It forms \(NCl_3\), \(N_2O_5\), and \(Ca_3N_2\) but does not form \(NCl_5\).

### Final Answer:
The element 'X' is **Nitrogen (N)**.