Given the reaction N2 + 3H2 -->2NH3, what volume of hydrogen is necessary to react with five liters of nitrogen to produce ammonia, assuming constant temperature and pressure?
Assuming complete reaction with no excess of reactants, the addition of reactants will be based on stoichiometry.
Assuming ideal gas behaviour, the addition of reactant by volume will be based on its stoichiometric coefficient. This means that reaction between 1 mole of reactant A with 3 mole of reactant B is the same as X L of reactant A with 3X L of reactant B. This is true because volume is proportional to number of moles in the ideal gas relation (PV=nRT)