What is the test and observation used to identify halide ions (Cl-, Br-, I-)?

Halide ions, such as chloride (Cl-), bromide (Br-), and iodide (I-), can be identified through a reaction with silver nitrate (AgNO3). When halide ions are added to a solution of silver nitrate, they react to form silver halides, which are insoluble precipitates. Each type of halide leads to a different colored precipitate:

• Silver chloride (AgCl) forms a white precipitate.
• Silver bromide (AgBr) yields a pale yellow precipitate.
• Silver iodide (AgI) results in a bright yellow precipitate.

This method is reliable because the distinct colors of the precipitates allow for easy visual differentiation between the various halide ions. The specificity of the colors produced directly correlates to the identity of the halide present in the solution, making this method a common and effective qualitative test in chemistry for identifying halide ions.