To solve this question, we need to look at the stoichiometric ratio between oxygen and SO₃, which in this case is 1:2
So 1 mole of O2 produces 2 moles of SO3.
Now we can use the rule of 3:
1 mole O2 --- 2 mole SO3
x mole O2 --- 8.46 moles SO3
2x = 1 x 8.46
x = 8.46/2
x = 4.23
Answer: 4.23 moles of O2
