Answer:
Since we have a large amount of N2 present, we know that H2 is the limiting reagent in this reaction
the reaction:
3 H₂ + N₂ --> 2 NH₃
so to get 2 moles of ammonia, we need to use 3 moles of hydrogen gas and we don't have to worry about the amount of nitrogen since we have an excess of it
Since we have 28 moles of hydrogen, 27 of which will react 3 at a time and we will be left with 1 extra mole of hydrogen
hence, 27 moles of h2 will react
since the ratio of moles of ammonia and the moles of hydrogen is 2/3
so, moles of hydrogen * 2/3 = moles of ammonia
27 * 2/3 = 18 Moles of Ammonia
