While 0.40 g of impure zinc reacted with an excess of hydrochloric acid, 127 mL of hydrogen was collected over water at 10 oC the external pressure was 737.7 Torr. Explain what is the percentage purity of the zinc, presuming that all the zinc present reacted completely with HCl as well as that the impurities didn't react with HCl to produce hydrogen? IF the vapor pressure of water at 10 degrees C is 9.21 Torr.