When we test for chloride, bromide and iodide ions we use the obvious silver nitrate and dilute nitric acid test. However distinguishing between the precipitates is often quite tricky. How can we tell the difference between a white, cream or yellow precipitate respectively. I understand we could use aqueous ammonia for the white precipitate, and that if it dissolved it would indicate the presence of chloride ions. However, the next two are much more difficult given my circumstances. With my practical test only aqueous ammonia is supplied, so I do not have access to concentrated ammonia. So what should I do now to distinguish between the remaining bromide and iodide ions?
Are there any tips such as holding white paper behind it to help me distinguish the two?