A mixture of 50.0 mL of NH3 and 60.0 mL of O2 gas reacts as4NH3(g)+5O2(g)⟶4NO+6H2O(g)If all the gases are at the same temperature and pressure and the reaction continues until one of the gases is completely consumed, what volume of water vapour is produced?

By Avogadro's law, equal volumes of gases contain equal number of moles.4NH3(g)+5O2(g)⟶4NO(g)+6H2O(g)                     4mLNH3=6mLH2O∴ 50mLNH3=75mLH2O               5mLO2=6mLH2O ∴ 60mLO2=72mLH2O stoichiometrically, O2 is consumed completely Thus, 72 mLH2O (g).