Chapter 6, Problem 8DQ

Le Châtelier’s principle is stated (Section 6.8) as “If agaseous reactant or product is added to a system at equilibrium,the system will shift away from the added component.”The system ${\text{N}}_2\text{(}g{\text{)+3H}}_2\text{(}g\text{)}\rightleftharpoons 2{\text{NH}}_{\text{3}}\left(g\right)$ isused as an example in which the addition of nitrogen gasat equilibrium results in a decrease in ${\text{H}}_{\text{2}}$ concentrationand an increase in ${\text{NH}}_{\text{3}}$ concentration as equilibrium isreestablished. In this experiment the volume is assumedto be constant. On the other hand, if ${\text{N}}_{\text{2}}$ is added to thereaction system in a container with a piston so that thepressure can be held constant, the concentration of ${\text{NH}}_{\text{3}}$ could actually decrease and the concentration of ${\text{H}}_{\text{2}}$ would increase as equilibrium is reestablished. Explainhow this is possible. Also, if you consider this same systemat equilibrium, the addition of an inert gas, at constantpressure, does affect the equilibrium position. Howis the equilibrium position affected? Explain.