a) with addition of Na2CrO4 the solubility of silver chromate will be reduced as there are more chromate ions in the solution which are coming from sodium chromate
b) with addition of HCl silver chromate solubility will increase as silver chromate reacts with HCl to produce silver chloride precipitate (white). silver chromate is red-brown color hence it can be easily distinguished
c) with NH3 silver chromate will form diamine complex and results in increased solubility of silver chromate
