# P + Cl_2 -> PCl_3 is what type of reaction?

Jun 2, 2017

All pure elements, which both reactants in this case are, have an oxidation state of $0$. When the product ${\text{PCl}}_{3}$ is formed, the oxidation state [or, although incorrect (but possibly more familiar), "charge"] of $\text{Cl}$ dropped from $0$ to $- 1$. Since the oxidation state decreased, the chlorine was reduced. Conversely, the oxidation state of phosphorus increased from $0$ to $+ 3$, so $\text{P}$ was oxidized.