An experiment is being carried out by two students. Anne tests the filtrate of a salt mixture with CaCl 2 in one test tube, while Phil tests the same filtrate with K 2 C 2 O 4 in a second test tube. Phil observes a white precipitate, while Anne does not. Which reactant is limiting in the original salt mixture? Explain. Solution Anne test : does not form precipitate The solution is unsaturated. Untill excess of CaCl2 is added, no precipitate would form here. Limiting reactant = CaCl2 Phil test : white precipitate formed The solution is saturated. All of ion in solution has reacted with added reagent. Reagent is in excess. Limiting reactant : Filtrate solution .