Ammonia is formed industrially by reacting nitrogen and hydrogen gases. how many liters of ammonia gas can be formed from 13.7 l of hydrogen gas at 93.0°c and a pressure of 40.0 kpa?

The balanced equation for the formation of ammonia is as follows;
N₂ + 3H₂ --> 2NH₃
Stoichiometry of H₂ to NH₃ is 3:2
at constant pressure and temperature, the number of moles of a gas is directly proportional to the volume of a gas. 
therefore number of moles are directly proportional to volume.
then the molar ratio of reactants to products is equivalent to volume ratios of reactants to products. then volume ratio of H₂ to NH₃ is 3:2
if 3 L of H₂ produce 2 L of NH₃
then 13.7 L of H₂ form - 2/3 x 13.7 = 9.13 L
a volume of 9.13 L of NH₃ is formed