In the synthesis of ammonia from its constituent elements, what is the coefficient of hydrogen in the stoichiometric equation?

1 Answer
Apr 15, 2017

Well, I would write #3/2#........


i.e. #1/2N_2(g)+3/2H_2(g) rightleftharpoons NH_3(g)#

This is a high pressure process, which could also be represented as,

#N_2 + 3H_2 rightleftharpoons 2NH_3#

The reaction is normally carried out at 200 atm and high temperatures, and catalyzed on metal or metal oxide surfaces. It is one of the most important industrial reactions, in that without such a reaction we would not be able to grow nitrogenous fertilizer with which to grow food.

Given the bond energy of the #N-=N# bond, about the only thing this reaction has got going for it is the relative involatility/solubility of ammonia compared to the parent gases. Even a small turnover at equilibrium could be removed from the process, and the equilibrium reshunted to the right to make more product.