sodium hydroxide solution is added to the solid or aqueous substance to be tested and heated. Ammonia gas is produced and turns red litmus paper blue.
How to test for carbonate ions?
React the substance with hydrochloric acid (HCl).If the substance contains a carbonate ion, carbon dioxide gas will bubble out of the solution, Collect the gas and bubble it through limewater, If the limewater turns cloudy, it confirms the gas is carbon dioxide.
How to test for sulfate ions?
Add a barium salt solution for example, BaCl2 and a white precipitate will form
How to test for halide ions
Firstly, add HNO3 (nitric acid) to remove carbonate ions, then add AgNO3 (silver nitrate)
