Question

The equillibrium constant (Kp) for the interconversion of PCl5 and PCl3 is 0.0121:

PCl5(g) --> PCl3(g) + Cl2(g)

A vessel is charged with PCl5, giving a initial pressure of 0.123 atm. At equillibrium, the partial pressure of PCl3 is _____ atm.

Answer 1

.........PCl5 ==> PCl3 + Cl2
initial...0.123.....0.......0
change...-2p........p.......p
equil...0.123-2p.....p......p

Substitute the equilibrium values into the expression for Kp and solve for p.
Post your work if you get stuck.

Answer 2

.0330