Reaction equation:
2H₂ + O₂ → 2H₂O
150 moles of Hydrogen requires 75 moles of Oxygen; however, 70 moles of Oxygen are present so Oxygen is the limiting reactant. We will calculate the amount of product using the amount of Oxygen.
Molar ratio of Oxygen : water:
1 : 2
Thus, moles of water = 2 x moles of oxygen
Moles of water = 2 x 70
Moles of water = 140