Ammonium salts and nitric acid are primarily manufactured from which substance?

Ammonium salts and nitric acid are primarily manufactured from ammonia because ammonia is a key starting material in the production of these compounds. In the synthesis of ammonium salts, ammonia reacts with acids, including nitric acid, to form various ammonium salts. Additionally, ammonia is used in the Haber process to create fertilizers and is essential in agricultural applications.

In the context of nitric acid production, ammonia can be oxidized to produce nitric oxide, which is further converted into nitric acid through a series of chemical reactions. This process is critical for producing nitric acid that is then used to create ammonium nitrate, a widely used fertilizer.

Other choices do not serve as primary raw materials for the production of ammonium salts and nitric acid. Chlorine has different applications primarily in disinfection and the production of chlorinated compounds. Urea, while related to nitrogen fertilizers, is not directly processed into ammonium salts. Phosphate rock is primarily a source of phosphorus and relates to different fertilizers altogether, focusing on phosphorus rather than nitrogen. Therefore, ammonia is the correct choice, as it is fundamentally linked to the production of both ammonium salts and nitric acid.