Answer to Question #57567 in General Chemistry for Tracy Guido

Question

what is the chemical formula for the compound that is added to make all of the silver ions form precipitates? would this be HCl or Cl2

Silver Group Cations - Ag+, Pb2+ and Hg22+ Which of the silver group ions is most soluble in hot water (PbCl2 is what this says in the lab book)water, where does the Cl2 come from and which ion undergoes a complexation reaction?

Answer 1

It can be HCl or any salt with Cl- (such as NaCl, KCl), but not Cl2. Cl2 would not react directly with
silver; it would form HCl and HClO first by reaction with water. Also Cl2 is very toxic gas.
Yes, PbCl2 is most soluble (you can check this by comparing dissociation constants in the
reference book). Cl comes from the anion part of your compound. For example
Pb(NO3)2 + 2HCl = PbCl2 + 2HNO3
Complexation goes between Pb2+ and Cl- ions:
Pb2+ + 2Cl- = PbCl2