What happens when `PCl_5` is heated?

Explanation

When phosphorus pentachloride (PCl₅) is heated, it undergoes decomposition. The reaction can be summarized as follows:

1. **Decomposition Reaction**: When PCl₅ is heated, it breaks down into phosphorus trichloride (PCl₃) and chlorine gas (Cl₂). The balanced chemical equation for this reaction is:
\[ \text{PCl}_5 \, (s) \, \xrightarrow{\text{heat}} \, \text{PCl}_3 \, (g) + \text{Cl}_2 \, (g) \]

2. **Molecular Geometry**: The molecular geometry of PCl₅ is trigonal bipyramidal, where phosphorus is at the center, and the five chlorine atoms are arranged around it. Upon decomposition, PCl₃ has a trigonal pyramidal shape, with three chlorine atoms bonded to phosphorus and one lone pair of electrons on the phosphorus atom.
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