Question

Which of the following reaction stoichiometry would be used to calculate the moles of H₂O formed when a given mole of NH₃ completely react with excess amount of O₂?

4 NH₃ + 5 O₂ → 4 NO + 6 H₂O

a. 6 mol H2O/4 mol NH3

b. 4 mol NH3/6 mol H2O

c. 5 mol O2/4 mol NH3

d. 4 mol NH3/5 mol O2

Answer 1

The reaction between NH3 and O2 to form NO and H2 is-

4 NH₃ + 5 O₂ → 4 NO + 6 H₂O

That means if we take 4 mols of NH3 and react it with excess amount i.e sufficient amount of O2, then we will get 6 moles of H2O from it. Thus the ratio between NH3 and H2O is=

4 mol NH3 / 6 mol H2O = 4 : 6 or 2 : 3

Thus if we know that we have taken x mol of NH3 then we will get (3/2)x mol of H2O