Consider the following equilibrium. 2 SO2 (g) + O2 (g) 2 SO3 (g) The equilibrium cannot be established when __________ is/are placed in a 1.0-L container.

2 answers

the answer is 0.75mol SO2 but I don't understand where to even begin
I don't get it. It appears to me that any number one chooses can go there. Without O2 along with SO2 there is no way to establish equilibrium for SO2 alone or for O2 alone.