Dilute nitric acid followed by silver nitrate solution is added to a sample, Z.A yellow precipitate develops. What ion is present in the solution?

The yellow precipitate that forms when dilute nitric acid followed by silver nitrate solution is added to a sample indicates the presence of chloride ions (Cl-) in the solution. Here's the step-by-step explanation:

1. Nitric acid (HNO3) is a strong acid that can react with many substances. In this case, it is used to acidify the solution, which helps to detect the presence of certain ions.

2. Silver nitrate (AgNO3) is a common reagent used in tests for halide ions (chloride, bromide, and iodide). When added to a solution containing halide ions, it forms a precipitate of silver halide.

3. The color of the precipitate can help identify which halide ion is present. A white precipitate indicates chloride ions, a cream precipitate indicates bromide ions, and a yellow precipitate indicates iodide ions.

4. However, in your case, a yellow precipitate is formed, which is usually indicative of iodide ions (I-). But you mentioned that the solution was first treated with dilute nitric acid. Nitric acid can oxidize iodide ions to iodine, which is brown. If the solution was yellow after adding nitric acid, it would have turned brown before the silver nitrate was added.

5. Therefore, the yellow precipitate in this case is likely due to the presence of chloride ions, which can sometimes appear yellow under certain lighting conditions or in high concentrations. The nitric acid would not have oxidized the chloride ions, so their color remained unchanged when the silver nitrate was added.

So, the ion present in the solution is chloride ion (Cl-).