The question is:
1 mole of nitrogen gas and 3 moles of hydrogen gas were added to a rigid 1 L container at 298 K and left to react. At equilibrium it was found that the concentrations of nitrogen, hydrogen and ammonia were 0.116 mol L–1, 0.348 mol L–1 and 1.768 mol L–1 and the pressure inside the container was 55 bar.
1 mole of hydrogen chloride gas was subsequently added to the container and the system was left to re-establish equilibrium (hydrogen chloride gas reacts with ammonia gas to produce solid ammonium chloride).
What are the concentrations (or range of concentrations) of nitrogen, hydrogen, ammonia and hydrogen chloride once equilibrium has been reached for the second time?
I have attached the multi-choice answers.
So the 2 equations after HCl was added is:
HCl + NH3
So after HCl is added the ammonia will react with it creating NH4
Cl. So therefore the N2
will increase forward reaction to balance the equilibrium. So A and C are ruled out. The ammonia will react to form NH4
Cl so B is also ruled out. Now I am left with D and E, I choose E since some NH4
Cl will dissociate back into HCl + NH3
. However, the answer is D. I can't think of any reason the HCl concentration would be 0, if HCl is 0 then the equilibrium constant for HCl and NH3
Can someone give me a hint as to why the HCl concentration would be 0?