Question

What test reagent used in this experiment will distinguish a soluble cl- salt from so42- salt? what is the distinguishing observation?

Answer 1

The two ions to be distinguished are : Chloride ion and sulphate ion

The chloride ion can be identified by addition of silver nitrate to the solution containing chloride ion

On addition of silver nitrate, chloride ion will react with silver ions to form a white precipitate of silver chloride

The reaction is

Ag+ (a)  + Cl-(aq)  ---> AgCl(s)

the solution containing sulphate ion can be identified by adding barium chloride

Ba+2  + SO4^-2   ----> BaSO4(s), white ppt

thus barium chloride reacts with sulphate ion to form white ppt