Which of the following statements are not correct?

Options

A. NaCl being an ioninc compound is a good conductor of electricity in the solid state
B. In canonical structure there is a difference in the arrangement of atoms.
C. Hybrid orbitals form stronger bonds than pure orbitals.
D. VSEPR theory can explain the square planar geometry of `XeF_(4)`

Explanation

To determine which statements are not correct, we will evaluate each statement one by one.

### Step-by-Step Solution:

1. **Evaluate Statement 1:**
- Statement: "NaCl being an ionic compound is a good conductor of electricity in solid state."
- Analysis: Ionic compounds like NaCl conduct electricity when they are dissolved in water or molten because the ions are free to move. However, in the solid state, the ions are fixed in place within the crystal lattice and cannot move freely. Therefore, NaCl in solid state is a poor conductor of electricity.
- Conclusion: This statement is **not correct**.

2. **Evaluate Statement 2:**
- Statement: "In canonical structures, there is a difference in the arrangement of atoms."
- Analysis: Canonical structures (or resonance structures) differ in the arrangement of electrons, not in the arrangement of atoms. The positions of the atoms remain the same; only the distribution of electrons changes.
- Conclusion: This statement is **not correct**.

3. **Evaluate Statement 3:**
- Statement: "Hybrid orbitals form stronger bonds than pure orbitals."
- Analysis: Hybrid orbitals are formed by the combination of atomic orbitals and are generally more effective in forming stronger bonds due to better overlap with the orbitals of other atoms. This statement is true.
- Conclusion: This statement is **correct**.

4. **Evaluate Statement 4:**
- Statement: "VSEPR theory can explain the square planar geometry of XeF4."
- Analysis: The hybridization of XeF4 is sp3d2, which corresponds to a square planar geometry. VSEPR theory can indeed explain this geometry based on the arrangement of bonding pairs and lone pairs around the central atom.
- Conclusion: This statement is **correct**.

### Final Answer:
The statements that are **not correct** are **1 and 2**.