Qualitative ysis of Cations?

i ran an experiment to identify cations in an unknown solution. From the following possible cations of: Ag+, Pb2+, Hg (1) ions, Fe3+, Cu2+, Mn2+, Zn2+, Al3+, Co2+, and Bi3+, i concluded that i had Ag+, Al3+, and Zn2+. However on a certain step that involved the addition of 10 drops of 3% H2O2 and NaOH, a yellow/white precipitate formed, and after adding sulfuric acid, the precipitate turned white. My question is "What is the cation that formed the yellow precipitate?"