Seriously though
people love to do that stuff .-.
The answer is 0.5 moles because if 1 moles of o2 is consumed to produce 2 moles of Na2O, then 0.5 moles of o2 will be consumed to produce 1 mole of Na2O.<span />
Since Kw= [H⁺][OH⁻], and the concentration of both substances are the same, the equation is now Kw=[H⁺]²
So,
3.31x10⁻¹³ = [H⁺]²
Take the square root= 5.75x10⁻⁷
Then take the negative log to find the pH:
-log(5.75x10⁻⁷) = 6.25
ANSWER: C. Simple machine