Introduction
Phosphorus trichloride (PCl₃) and antimony trichloride (SbCl₃) exhibit distinct behaviors when interacting with water. Understanding their reactivity can provide insight into their chemical properties.

PCl₃ Behavior with Water
- PCl₃ is a polar covalent compound.
- When it comes in contact with water, it reacts vigorously.
- The reaction produces phosphoric acid (H₃PO₄) and hydrochloric acid (HCl):
- **Reaction**: PCl₃ + 3 H₂O → H₃PO₄ + 3 HCl
- This reaction is exothermic and releases heat, making PCl₃ a strong electrophile.

SbCl₃ Behavior with Water
- SbCl₃ is also polar but behaves differently due to its molecular structure and the presence of a larger central atom.
- When SbCl₃ contacts water, it hydrolyzes to form antimony oxide (Sb₂O₃) and hydrochloric acid (HCl) more slowly:
- **Reaction**: 2 SbCl₃ + 3 H₂O → Sb₂O₃ + 6 HCl
- This reaction is less vigorous compared to PCl₃, indicating a lower reactivity with water.

Comparison of Reactivity
- **PCl₃**:
- Reacts quickly and vigorously with water.
- Forms phosphoric acid and HCl.
- **SbCl₃**:
- Reacts slowly and less vigorously.
- Forms antimony oxide and HCl.

Conclusion
The differing behaviors of PCl₃ and SbCl₃ with water can be attributed to their molecular structures and the nature of their interactions with water. PCl₃ shows high reactivity, while SbCl₃ exhibits milder hydrolysis, leading to different products and reaction rates.