EQUILIBRIUM: Given the equation

Question

2 PbS(s) + 3 O2(g) 2 PbO(s) + 2 SO2(g)
What direction will the reaction proceed if additional SO2 was added to the system at equilibrium?

Forward
Reverse
Nothing Happens
Difficult to determine

You really need to do this yourself. LeChatelier's Principle states that a system at equilibrium WILL SHIFT in such a way as to relieve the stress that has been applied. SO, adding SO2 (g) to the system makes the SO2 concentration too large. The reaction, then, will shift so as to remove some of the SO2. Which way must the reaction move in order to DECREASE the SO2? [I realize that "difficult to determine" may be an answer for some students but you know that isn't correct.:-)]

Answer 1

nothing happens

Answer 2

constant