Idea of the experiment: (1) Qualitative investigation of [Bi 3+ ] in a systemic cycle. (2) Preparation of different [Bi 3+ ] compounds. (3) Inter-conversion of [Bi 3+ ] compounds. Systemic Investigation of [Bi 3+ ] SI - 4 Systemic Investigation of [Bi 3+ ] SI - 4

Bismuth tetraiodide ion (orange colour) White ppt. Bismuth hydroxide (Yellow color) Bismuth triiodide Exp. 1 Exp. 2 Exp. 3 HNO 3 Ag + Nitrate Salt (SI-4) Reagents Used: (1) Acid: HNO 3.: (1:1 solution). (2) Alkali: NaOH (0.1 M solution).

(3) Salts: Potassium Iodide. Bismuth nitrate. Add (1 ml) of sodium hydroxide solution to ca. (2 ml) of Bismuth nitrate. What do you observe? Exp. 1 Observation: White ppt. of bismuth hydroxide. Equation:

Dissolve the precipitate from experiment (1) in (1 ml) dil. HNO 3, and then add (3 ml) of potassium iodide solution to the solution produced from exp.2. What do you observe? Exp. 2 Observation: Yellow ppt. of bismuth triiodide. Equation:

Dissolve the precipitate obtained from exp.2 in excess of KI solution. What do you observe? Exp. 3 The precipitate dissolves in KI forming orange colour of the complex. Observation: Equation: Finally Dissolve the complex formed from exp.3 in a few drops of conc HNO 3. The product is the starting solution of Bismuth nitrate. Finally Dissolve the complex formed from exp.3 in a few drops of conc HNO 3. The product is the starting solution of Bismuth nitrate.

Idea of the experiment: (1) Qualitative investigation of [Cu ++ ] in a systemic cycle. (2) Preparation of different [Cu ++ ] compounds. (3) Inter-conversion of [Cu ++ ] compounds. Systemic Investigation of [Cu ++ ] SI - 5 Systemic Investigation of [Cu ++ ] SI - 5

Exp.1 Cu ++ Exp.2 Exp.3 Nitrate salt Dark blue solution Exp.4 Bluish white ppt Copper carbonate (Pale blue ppt) Copper oxalate HNO 3 Blue ppt. Copper hydroxide (SI - 5)

Reagents Used: (1) Acid: HCl: (1:1 solution). (2) Salts: Sodium oxalate. Sodium carbonate. Sodium hydroxide. Capper nitrate, (5 gm) of the solid dissolved in (100 ml) of distilled water. HNO 3 (3) Ammonium hydroxide.

Add (1 ml) of sodium oxalate solution to ca. (2 ml) of copper solution. What do you observe? Exp. 1 Observation: Pale blue ppt. Of Copper oxalate. Equation: Dissolve the precipitate from experiment (1) in (1ml) NH 3 solution. What do you observe? Exp. 2

Observation: Dark blue solution. Add (1 ml) of HCl to the solution produced from exp. 2 and then add (2ml) of Na 2 CO 3. What do you observe? Exp. 3 Observation: Bluish white ppt. of CuCO 3. Equation:

Dissolve the precipitate obtained from exp. 3 in (0.5 ml) of HCl and then add few drops of NaOH. What do you observe? Exp. 4 Observation: Blue ppt. of Cu (OH) 2. Equation: Finally Dissolving the Cu(OH) 2 precipitate in conc HNO 3. The product is the starting solution of copper nitrate. Finally Dissolving the Cu(OH) 2 precipitate in conc HNO 3. The product is the starting solution of copper nitrate.

Systemic Investigation of [Hg 2+ ] SI - 6 Systemic Investigation of [Hg 2+ ] SI - 6 Idea of the experiment: (1) Qualitative investigation of [Hg 2+ ] in a systemic cycle. (2) Preparation of different [Hg 2+ ] compounds. (3) Inter-conversion of [Hg 2+ ] compounds.

Reagents Used: (1) Acids: HCl. Exp.1 Exp.2 Exp.4Chloride Salt Exp.3 Hg 2+ Yellow ppt. mercuric oxide white ppt. amino mercuric chloride Red ppt. mercuric iodide (SI - 6) (2) Alkali: Sodium hydroxide. Ammonium hydroxide.

Add (1 ml) of NH 4 OH to (2 ml) of the mercuric chloride solution. What do you observe? Exp. 1 Observation: White ppt. of amino mercuric chloride. Equation: (3) Salts: Mercuric chloride. Potassium iodide.

Observation: Yellow ppt. of mercuric oxide. Equation: Dissolve the precipitate obtained from experiment (1) in (1-2ml) HCl and then add (2ml) of NaOH. What do you observe? Exp. 2 Dissolve the precipitate obtained from experiment (2) in (0.5ml) HCl and then add a few drops of KI. What do you observe? Exp. 3

Equation: Observation: Red (initially yellow) precipitate of mercuric iodide. Observation: The red ppt. dissolves in excess KI and form a complex salt of potassium mercuric-iodide K 2 [Hg I 4 ]. Add another (2ml) of KI to the precipitate obtained from exp. 3. What do you observe? Exp. 4

Finally Addition of a few drops of conc. HCl to the complex obtained from exp. 4, gives the starting solution of mercuric chloride. Finally Addition of a few drops of conc. HCl to the complex obtained from exp. 4, gives the starting solution of mercuric chloride. Equation:

IF EXP. (II) GIVES NO PRECIPITATE THEN CARRY OUT EXP. III EXPERIMENT. III To (1ml) of the unknown solution add (2 ml) of ammonium chloride solution and (1 ml) of ammo- nium hydroxide solution Observation:

Systemic Investigation of [Cr 3+ ] SI - 7 Systemic Investigation of [Cr 3+ ] SI - 7 Idea of experiment: (1) Qualitative investigation of [Cr 3+ ] in a systemic cycle. (2) Preparation of different [Cr 3+ ] compounds. (3) Inter-conversion of [Cr 3+ ] compounds.

Reagents Used: (1) Acids: HCl: (1:1 solution). H 2 SO 4 (1:1 solution). (2) Alkali: NH 4 OH (0.1 M solution). NaOH (0.1 M solution). Exp.1 Cr 3+ (Yellow solution.) Cadmium hydroxide Exp.2 Exp.3 (SI - 7) (grey green ppt.) Cadmium hydroxide

(3) Salts: Chromium sulfate. Amm. Chloride. Sodium nitrite. Exp. 1 Add (1ml) of the unknown salt solution to (2ml) of ammonium chloride and (1ml) of ammonium hydroxide solution. What do you observe? Observation: Grey-green ppt. of chromium hydroxide. Equation: (4) Hydrogen peroxide, (30%).

Observation: The green ppt. dissolves and changed to a yellow solution of chromate. Exp. 2 Add (2 ml) of sodium hydroxide solution and (1 ml) of hydrogen peroxide solution to the precipitate obtained from experiment (1), and boil. What do you observe? Equation:

Add (1 ml) of H 2 SO 4 and (2 ml) of sodium nitrite solution to the solution obtained from exp. 2 to return to Cr 3+ solution again. What do you observe? Exp. 3 Observation: The yellow solution of chromate is reduced to the green solution of Cr 3+. Equation: