**Practice Problem 4**

Assume the following initial concentrations: (PCl_{5})
= 0.100 *M* and (Cl_{2}) = 0.020 *M*.
Calculate the equilibrium concentrations of PCl_{5}, PCl_{3},
and Cl_{2} if the equilibrium constant for the
decomposition of PCl_{5} is 0.030.

**Answer**

[PCl_{5}] = 0.065 *M*

[PCl_{3}] = 0.035 *M*

[Cl_{2}] = 0.055 *M*