1. Idea of the experiment: (1) Qualitative investigation of [Zn 2+ ] in a systemic cycle. (2) Preparation of different [Zn 2+ ] compounds. (3) Inter-conversion of [Zn 2+ ] compounds. Systemic Investigation of [Zn 2+ ] (SI - 13) Systemic Investigation of [Zn 2+ ] (SI - 13)

2. White ppt. Zn 3 (PO 4 ) 2 White gel. ppt. Zn (OH) 2 Solution Na[ZnO 2 ] Exp. 1 Exp. 2 Exp. 3 HCl Zn 2+ (SI-13) Reagents Used: - HCl (1:1 solution). - Sodium phosphate. - Sodium hydroxide. - Zinc chloride.

3. Add (1 ml) of sodium hydroxide solution to ca. (2 ml) of zinc chloride solution. What do you observe? Exp. 1 Observation: White gel. ppt. of Zn(OH) 2. Equation: Dissolve the precipitate obtained from experiment (1) in ca. (2 ml) NaOH solution. What do you observe? Exp. 2

4. Observation: The precipitate dissolves in NaOH. Equation: 1. Add (1 ml) of HCl to the solution produced from exp. 2. What do you observe? Exp. 3 Observation: White ppt. of Zn(OH) 2. Equation:

5. Finally Dissolving the Zn 3 (PO 4 ) 2 precipitate in HCl, gives the starting solution of ZnCl 2. Finally Dissolving the Zn 3 (PO 4 ) 2 precipitate in HCl, gives the starting solution of ZnCl 2. 1- Dissolve the precipitate obtained in (0.5 ml) of HCl and then add few drops of sodium phosphate. What do you observe? White ppt. of Zn 3 (PO 4 ) 2. Observation: Equation:

6. IF EXP. (IV) GIVES NO PRECIPITATE THEN CARRY OUT EXP. V EXPERIMENT. V To (2 ml) of the unknown solution add (1 ml) of NH 4 Cl, NH 4 OH until just alkaline, then add (2 ml) of (NH 4 ) 2 CO 3 solution. Observation: White ppt. This means that the solution may be contains (Ba 2+, Sr 2+ or Ca 2+ ). Dissolve the white precipitate in hot acetic acid, then add (2 ml) of K 2 Cr 2 O 7 solution:

8. Systemic Investigation of [Ba 2+ ] (SI - 14) Systemic Investigation of [Ba 2+ ] (SI - 14) Idea of experiment: (1) Qualitative investigation of [Ba 2+ ] in a systemic cycle. (2) Preparation of different [Ba 2+ ] compounds. (3) Inter-conversion of [Ba 2+ ] compounds.

9. Reagents Used: - HNO 3 (1:1 solution). - Sodium Sulphite - Amm. Oxalate - Sodium hydroxide. - Barium nitrate. (SI - 14) Exp.1 Ba 2+ Exp.2 Nitrate salt White PPt. Barium sulphite White ppt. Barium hydroxide White ppt. Barium oxalate Exp.3 HNO 3

10. Exp. 1 Add (1 ml) of amm. oxalate solution to ca. (2 ml) of barium nitrate solution. What do you observe? Observation: White ppt. of barium oxalate. Equation: Exp. 2 Dissolve the precipitate from experiment (1) in (1 ml) dil. HNO 3, then add (1 ml) of sodium sulphite solution. What do you observe?

11. Observation: White ppt. of barium sulphite. Exp. 3 Dissolve the precipitate from experiment (2) in (1 ml) dil. HNO 3, then add (1 ml) of amm. hydroxide solution. What do you observe? Observation: White ppt. of barium hydroxide. Equation:

12. Finally Dissolve the precipitate formed from exp.3 in a few drops of HNO 3. The product is the starting solution of barium nitrate. Finally Dissolve the precipitate formed from exp.3 in a few drops of HNO 3. The product is the starting solution of barium nitrate. Idea of the experiment: (1) Qualitative investigation of [Sr 2+ ] in a systemic cycle. (2) Preparation of different [Sr 2+ ] compounds. (3) Inter-conversion of [Sr 2+ ] compounds. Systemic Investigation of [Sr 2+ ] (SI - 15) Systemic Investigation of [Sr 2+ ] (SI - 15)

13. Reagents Used: - HNO3 (1:1 Solution). - Strontium nitrate. - Sodium Carbonate. - Ammonium oxalate. Exp.1 Sr 2+ White ppt. Sr C 2 O 4 Exp.2 HNO 3 (SI - 15) White ppt. Sr CO 3 Nitrate salt

14. Exp. 1 Add (1 ml) of sodium carbonate solution to ca (2 ml) of (Sr 2+ )solution. What do you observe? Observation: White ppt. of strontium carbonate. Equation: Exp. 2 Dissolve the precipitate from experiment (1) in (1 ml) dil. HNO 3, then add (1 ml) of amm. oxalate solution. What do you observe? Observation: White ppt. of strontium oxalate.

15. Finally Dissolve the precipitate formed from exp.2 in a few drops of HNO 3. The product is the starting solution of strontium nitrate. Finally Dissolve the precipitate formed from exp.2 in a few drops of HNO 3. The product is the starting solution of strontium nitrate. Equation:

16. Idea of the experiment: (1) Qualitative investigation of [Ca 2+ ] in a systemic cycle. (2) Preparation of different [Ca 2+ ] compounds. (3) Inter-conversion of [Ca 2+ ] compounds. Systemic Investigation of [Ca 2+ ] (SI - 12) Systemic Investigation of [Ca 2+ ] (SI - 12)

17. Exp.1 Ca 2+ White ppt. CaC 2 O 4 Exp.2 HNO 3 (SI - 16) White ppt. CaCO 3 Nitrate salt Reagents Used: - HNO 3 (1:1 Solution). - Sodium Carbonate. - Ammonium Oxalate.

18. Add (1 ml) of sodium carbonate solution to ca (2 ml) of calcium nitrate solution. What do you observe? Exp. 1 Observation: White ppt. of calcium carbonate. Equation: Dissolve the precipitate from experiment (1) in (1ml) dil. HNO 3, and then add (1 ml) of amm. Oxalate solution. What do you observe? Exp. 2

19. Observation: White ppt. of calcium oxalate. Finally Dissolve the precipitate formed from exp.2 in a few drops of HNO 3. The product is the starting solution of calcium nitrate. Finally Dissolve the precipitate formed from exp.2 in a few drops of HNO 3. The product is the starting solution of calcium nitrate. Equation:

20. IF EXP. (V) GIVES NO PRECIPITATE THEN CARRY OUT EXP. VI EXPERIMENT. VI To (1 ml) of unknown solution add sodium hydroxide and then boil. Observation:

21. Systemic Investigation of [Mg 2+ ] (SI - 17) Systemic Investigation of [Mg 2+ ] (SI - 17) Idea of experiment: (1) Qualitative investigation of [Mg 2+ ] in a systemic cycle. (2) Preparation of different [Mg 2+ ] compounds. (3) Inter-conversion of [Mg 2+ ] compounds.

22. Reagents Used: - HCl (1:1 solution). - Amm. Hydroxide. - Magnesium Chloride - Amm. Chloride. - Sod. Phosphate. White gel. ppt. Mg (OH) 2 White ppt. Mg (NH 4 ) PO 4 Exp. 1 Exp. 2 HCl Mg 2+ (SI-13)

23. Exp. 1 To (2 ml) of MgCl 2 solution, add (1 ml) of NH 4 OH until just alkaline. What do you observe? Observation: White gelatinous ppt. of. Magnesium hydroxide. Equation: Exp. 2 Dissolve the precipitate formed from exp.2 in a few drops of HCl, then add sodium phosphate solution in the presence of amm. chloride and ammonia solution.(cool the tube). What do you observe?

24. Observation: White crystalline precipitate from magnesium ammonium phosphate. (slow formation of ppt.). Exp. 3 Dissolve the precipitate from experiment (1) in (1 ml) dil. HCl, then add (1ml) of sodium hydroxide. What do you observe? Observation: White ppt. of Mg (OH) 2. Equation:

25. Finally Dissolve the precipitate formed in exp.3 in dil HCl. The product is the starting solution of magnesium chloride. Finally Dissolve the precipitate formed in exp.3 in dil HCl. The product is the starting solution of magnesium chloride. Exp. VI-A To (1 ml) of the unknown solution add (1 ml). of Nessler`s reagent. K 2 [HgI 4 ]. What do you observe? Observation: Brown ppt., or brown or yellow coloration, is produced according to the amount of ammonia or of ammonium ions. (NH 4 ) 2 [HgI 4 ]. Test for Ammonium radical:

26. Exp. VI-B To (1 ml) of the unknown solution add (1 ml). of sodium cobaltinitrite solution. What do you observe? Observation: Yellow precipitate of potassium-sodium cobalti- nitrite Test for potassium radical: Equation: If exp. VI-B gives no observation, then the solution contains Na + radical.