List a reagent that will separate the following mixtures by formation of a precipitate. List the Precipitate.?

Question

1.Ba(NO3)3 (aq) & FeCl3(aq)

2. LiNO3(aq) & AgNO3(aq)

3. Pb(NO3)2(aq) & AgNO3(aq)

4. Mg(NO3)2(aq) & NaNO3(aq)

Answer 1

1) Sulphuric acid will form a ppt with Ba 2+ as barium sulphate is insoluble. It wont form with Fe3+ as iron sulphate is soluble.

2)HCl will form a ppt with Ag (AgCl is insoluble)

3)Sodium sulphate can separate this. Lead sulphate is insoluble

4)Any carbonate can be used to separate this as Magnesium Carbonate forms a ppt.

Answer 2

1) Sulfuric acid will form Barium Sulfate. Iron is soluable in sulfate.

2) Hydrochloric Acid will form Silver Chloride. Lithium is soluable in chloride.

3) Sodium Hydroxide will form Lead Hydroxide. Silver is soluable in hydroxide.

4) Sodium Carbonate solution will form Magnesium Carbonate. Sodium is soluable in carbonate.

The only problem with the first answer is that Silver Sulfate is also insoluable, so you won't get a good separation between lead and silver since both will precipite out.

Answer 3

Anthony and Duluth are each mostly correct. In 3., however you have to add NaCl to precipitate AgCl and PbCl2. Then you add NH3 (actually NH4OH). This dissolves AgCl, but not PbCl2. This is because of formation of soluble Ag(NH3)2+ ion.