How can silver nitrate be used to detect iodide ions in water?

To detect iodide ions in water using silver nitrate, you add the reagent to the water sample in the presence of dilute nitric acid.1

This process results in the formation of a yellow precipitate known as silver iodide. This precipitate is distinct because it is insoluble in both water and ammonia solution. This reaction serves as a reliable qualitative test for the presence of iodide ions in an aqueous solution.1