An aqueous solution contains metal cations Hg^+2 and Mn^+2 belonging to groups 2 and 3 respectively. Thioacetamide which produces H2S is added and the solution is buffered to a pH of 8 by addition of NH3/NH4Cl A) under these group 3 conditions what compounds will precipitate from solution B) if group 2 conditions are imposed by lowering the solution pH to 1 what compound(s) (if any) will remain precipitated?