The drain cleaner, Drainex contains small bits of aluminum which react with caustic soda to produce dihydrogen. What volume of dihydrogen at 20∘C and one bar will be released when 0.15g of aluminum reacts?
Solution: The balanced chemical equation is 2Al+2NaOH+2H2O→2NaAlO2+3H2. 54 g (2 mol) of Al will give 3 moles (or 67.2 L) of hydrogen. 0.15 g of Al will give 5467.2×0.15=0.189L of hydrogen. The volume of hydrogen is at 1 bar and 273 K. The volume at 1 bar and 200C will be, V′=P′TPVT′=1×2731×0.189×293=0.2028L=202.8ml.