What volume of hydrogen gas at STP would be liberated by action of 50 mL of H₂SO₄ of 50 % purity (density = 1.3 g mL ⁻¹ ) on 20 g of zinc ? Given : Molar mass of H, O, S, Zn are 1, 16, 32, 65 g mol ⁻¹ respectively.

Step-by-step solution

Mass of H₂SO₄ solution = 50 1.3 = 65 g Mass of pure H₂SO₄ = 65 50 100 = 32.5 g Moles of H₂SO₄ = 32.5 98 0.3316 mol Moles of Zn = 20 65 0.3077 mol The balanced chemical equation is: Zn + H₂SO₄ ZnSO₄ + H₂ Since the moles of Zn are less than the moles of H₂SO₄ , Zn is the limiting reagent. Moles of H₂ produced = Moles of Zn = 20 65 mol Volume of H₂ gas at STP = 20 65 22.4 L = 6.892 L Answer: 6.892 L