J.R. S. answered 05/06/20
Ph.D. University Professor with 10+ years Tutoring Experience
2SO2(g) + O2(g) <===> 2SO3(g)
2.6.............2.3.....................0.........Initial
-2x............-x.......................+2x......Change
1.41...........2.3-x...................................Equilibrium
Since we are told the initial and final [SO2], we can easily determine how much was used up.
2.6 - 2x = 1.41
2x = 1.19
x = 0.595
Since the equilibrium [O2] is 2.3 - x, it will be 2.3 - 0.595
[O2] = 1.71 mol/L