2 P + 5 Cl₂ → 2 PCl₅

Here's the breakdown:

* P: Phosphorus (solid)

* Cl₂: Chlorine gas

* PCl₅: Phosphorus pentachloride (solid)

Explanation:

* Phosphorus reacts vigorously with chlorine gas, producing a bright white flame.

* In excess chlorine, phosphorus reacts to form phosphorus pentachloride (PCl₅).

* The balanced equation shows that 2 moles of phosphorus react with 5 moles of chlorine gas to produce 2 moles of phosphorus pentachloride.