The equilibrium for the reaction for the decomposition of PCl5 to chlorine and PCl₃ is 0.042. PCl5(g) ⇌ PCl₃(g)+ Cl₂(g) If the equilibrium concentrations are [PCl₃ ] = 0.010 M, [Cl₂ ] = 0.10 M, what is the value of [PCl5]?

Question

Quizplus · Accepted Answer

Using the equilibrium expression, we can set up an ICE table:

PCl5(g) ⇌ PCl3(g) + Cl2(g)
I:       ?                0          0
C:    -0.010            +0.010      +0.10
E:   0.042-0.010    =0.032     =0.10

The equilibrium concentrations are found by subtracting the given concentrations from the equilibrium concentrations given in the problem. From the ICE table, we know that the equilibrium concentration of PCl5 is equal to the initial concentration minus the change, so [PCl5] = 0.042 - 0.032 = 0.010 M. Therefore, the answer is D, 0.024 M.

The Equilibrium for the Reaction for the Decomposition of PCl5