Which of the following is produced when phosphate rock is treated with nitric acid?

When phosphate rock is treated with nitric acid, the reaction primarily produces calcium nitrate and phosphoric acid. The process involves the nitric acid reacting with the phosphate rock, which contains calcium phosphate. The nitric acid dissolves the calcium phosphate, resulting in the formation of phosphoric acid and calcium nitrate. This is a significant chemical reaction in the production of fertilizers, as both the phosphoric acid and the calcium nitrate can be used to enhance soil fertility.

The reaction is important in agricultural practices because it provides plants with essential nutrients. Phosphoric acid supplies phosphorus, which is crucial for plant energy transfer, photosynthesis, and overall growth, while calcium nitrate provides both calcium and nitrogen, which are vital to plant health.

The other options refer to different processes or products not formed when phosphate rock specifically reacts with nitric acid. Single superphosphate and triple superphosphate are products formed by treating phosphate rock with sulfuric acid rather than nitric acid. Ammonium phosphate is derived from combining ammonium and phosphate sources, which does not occur directly from the reaction of phosphate rock with nitric acid. Thus, the best answer is the production of calcium nitrate and phosphoric acid through this specific chemical reaction.