Question

For this exercise, let's say that you begin with an aqueous mixture containing the following compounds: Ba(NO3)2, Mg(NO3)2, and AgNO3 You also have separate solutions, one of each: K2SO4 (aq), KCI (aq), and KOH(aq) Let's call these the challenge reagents. Your task is to propose a step-by-step procedure for sequentially separating the cations in your mixture. You must include . What challenge reagent to add, • Which cation will precipitate, • What is the equation for that reaction, and - How will you separate the precipitate from the rest of the mixture so you can go on to the next challenge reagent.

need to use solubility table to see if something solidifies/precipitates. I need help with figuring out which challenge reagents precipitate when reacting with the mixtures listed there. Ty!!

Answer 1

Aim of the experiment :Separation of cations from the mixture .

Apparatus: test tubes, beakers,tripod stand, funnel,filter paper,glass rod .

Chemical equations:

Step 1:

KCl + AgNO3 → KNO3+AgCl(white ppt)

Step 3:

Ba(NO3)2 + K2SO4 → BaSO4 (white or pale yellow ppt. )+ 2 KNO3

Step 4:

Mg(NO 3) 2 (aq) + 2 KOH (aq) → Mg(OH) 2 (white crystalline solid) + 2 KN O 3 (aq)

Chemical requirements : Mixture of Ba(NO3)2,Mg(NO3)2,Ag(NO3)2.

Challenge reagents: K2SO4(aqueous),KCl(aqueous),KOH(aqueous).

Procedure:

1.Take 1.00 ml of mixture of solutions in a test tube and to it add KCl (aq) challenge reagent and shake well. Then let the solution stand for a minute . A white colored precipitate of silver chloride is formed .

2. Then take a funnel and insert filter paper in the funnel and keep it on a tripod stand . Keep a beaker below the funnel to collect the filtrate. Wash the precipitate of silver Chloride with distilled water . This way group 1 cation  Ag+ is separated .

Note: All precipitates of chloride are soluble in water but silver chloride is insoluble .

3.Take another test tube and add the filterate  containing the mixture of Ba(NO3)2,Mg(NO3)2 .To this add K2SO4(aq.) ,it is observed that a white or pale yellow coloured crystalline precipitate is formed which is of Ba(SO)4.Thus group 2 cation Ba+2 is separated.Filter the precipitate and save the filtrate for next step .

4.To the remaining filtrate add KOH(aq) a solid substance is formed which is Magnisium hydroxide. Filter the solution and let it dry .

5. Thus, we get the cations .