15) 10 moles SO₂ and 15 moles O₂ were allowed to react over a suitable catalyst. 8 moles of SO₃ were formed. The remaining moles of SO₂ and O₂ are respectively:

16) If 0.5 mole of BaCl₂ is mixed with 0.2 mole of Na₃PO₄, the maximum amount of Ba₃(PO₄)₂ that can be formed is:

17) 4 gm NaOH is present in 100 mL of its aqueous solution. What is the molarity?

18) The solution of H₂SO₄ contains 80% by mass. Specific gravity of solution is 1.71 gm⁄cc. Find its molarity:

19) To neutralize 20 mL NaOH, the volume if 1M HNO₃ is: