Final answer:
To determine the ingredients used to make AgBr, one should perform a precipitation reaction. If Ag+ and Br- ions combine, AgBr will precipitate out as an insoluble salt. Barium sulphate presence can be tested by adding a sulfate salt to the solution, causing a white precipitate if BaSO4 is present.
Step-by-step explanation:
The student is asking about how to determine whether Ag+ (aq) or S2- (s) is used to make AgBr (s). The correct method is to perform a precipitation reaction. In this case, a precipitate of AgBr will form if Ag+ and Br- ions are present in the solutions mixed together. This is based on the solubility rules, which dictate that AgBr is insoluble in water and will precipitate out of solution.
To test for the presence of barium sulphate (BaSO4) in the products of a reaction, add a salt that produces a sulfate ion, such as Na2SO4, to the solution. If BaSO4 is present, it will form a white precipitate due to its low solubility in water.