Understanding the "Relationship between number of molecules"
In the Ostwald Process, 4 molecules of ammonia and 5 molecules of oxygen react to produce 4 molecules of nitric oxide and 6 molecules of water. Which of the following equations correctly models the relationship between the number of molecules of nitric oxide, n, and the number of molecules of water, w, produced by the reaction?
I would think that it would come down to 2n=3w, but the correct answer is 3n=2w. Can anyone help me understand why it would be this and not my guess?