Which reagent would you use to test for bromide ions by forming a cream precipitate?

Which reagent would you use to test for bromide ions by forming a cream precipitate?

• A. Silver nitrate
• B. Barium chloride
• C. Sodium hydroxide
• D. Copper sulfate

Answer: (A)

The test relies on silver ions forming insoluble silver halide precipitates with halide ions, and the color of the precipitate identifies which halide is present. For bromide, the precipitate is cream-colored, produced by silver bromide. So the reagent you add to generate that cream precipitate is silver nitrate (under acidic conditions). The other reagents wouldn’t give the characteristic cream AgBr precipitate with bromide—barium chloride tests for sulfate (not bromide), sodium hydroxide doesn’t selectively reveal bromide via a cream precipitate, and copper sulfate isn’t used for this halide test.

The test relies on silver ions forming insoluble silver halide precipitates with halide ions, and the color of the precipitate identifies which halide is present. For bromide, the precipitate is cream-colored, produced by silver bromide. So the reagent you add to generate that cream precipitate is silver nitrate (under acidic conditions). The other reagents wouldn’t give the characteristic cream AgBr precipitate with bromide—barium chloride tests for sulfate (not bromide), sodium hydroxide doesn’t selectively reveal bromide via a cream precipitate, and copper sulfate isn’t used for this halide test.