Flexi Says: The sodium reacts with water to produce sodium hydroxide and hydrogen gas. The chemical equation for the reaction is 2Na + 2H2O → 2NaOH + H2. The number of moles of Na given = 90/23 = 3.91 mol. The number of moles of water = 80/18 = 4.44 mol. Thus, Na is a limiting reagent in the reaction. Therefore, it is 3.91/2 = 1.96 mol of H2 is produced. Now 1 mol = 22.4 L, therefore 1.96 mol of H2 = 1.96 x 22.4 = 43.9 L of H2 is produced.