idea of the experiment: (1) qualitative investigation of [pb ++ ] in a systemic cycle. (2)...

Idea of the experiment:

(1) Qualitative investigation of [Pb++] in a systemic

cycle.

(2) Preparation of different [Pb++] compounds.

(3) Inter-conversion of [Pb++] compounds.

Systemic Investigation of [Pb+

+]

SI - 1

Systemic Investigation of [Pb+

+]

SI - 1

Exp.1

Exp.5

Pb++

Exp.2

Exp.3

Nitrate Salt

White ppt Lead carbonate

Lead Nitrate

Exp.4White ppt

Lead hydroxide

Yellow ppt Lead iodide

White ppt. Lead Oxalate

HNO3

(SI -1)

Reagents Used:

(1) Acids:

HCl, 1:1 solution.HNO3.

(2) Salts:

Sodium OxalateSodium CarbonatePotassium iodideLead nitrate, (5gm) of the solid salt in (100 ml) of distilled water.

(3) Ammonium hydroxide.

Add (1 ml) of sodium oxalate solution to (2 ml) of lead solution. What do you observe?

Exp. 1

Observation:

White ppt of lead osxlate.

Equation:

42342223 OPbC2NaNOOCNaNOPb

Dissolve the precipitate from the exp. (1) in (1ml) of dil HNO3.What do you observe?

Exp. 2

The precipitate dissolves in HNO3.

Observation:

Add (1 ml) of NH4OH to the solution produced from the exp.2.What do you observe?

Exp. 3

White ppt of lead hydroxide.

Observation:

Equation:

ClNH(OH)PbOHNHClPb 4242

Dissolve the precipitate obtained from the exp.3 in (0.5 ml) of HNO3 and then add few drop of Na2CO3.What do you observe?

Exp. 4

Observation:

White ppt of lead carbonate.

Equation:

333223 2NaNOCOPbCONaNOPb

Dissolve the precipitate obtained from exp.4 in (0.5 ml) of HNO3 and then add one or two drops from KI. What do you observe?

Exp. 5

Yellow ppt of lead iodide.

Observation:

Equation:

3223 2KNOIPb2KlNOPb

FinallyDissolve the precipitate obtained from exp.5 in a few drops of HNO3 and then heat. The product is the starting solution of Pb(NO3)2.

FinallyDissolve the precipitate obtained from exp.5 in a few drops of HNO3 and then heat. The product is the starting solution of Pb(NO3)2.

Systemic Investigation of [Ag+]

SI - 2

Systemic Investigation of [Ag+]

SI - 2

Idea of the experiment:

(1) Qualitative investigation of [Ag+] in a systemic

cycle.

(2) Preparation of different [Ag+] compounds.

(3) Inter-conversion of [Ag+] compounds.

White ppt. Silver phosphate

White ppt. Silver sulphite.

White ppt. Silver carbonate

Exp. 1

Exp. 2

Exp. 3

HNO3

Ag+

Silver nitrate.

(SI-2)

Reagents Used:

(1) Acids:

HNO3.: 1:1 solution.

(2) Salts:Sodium SulphiteSodium CarbonatePotassium phosphateSilver nitrate, (1.35) of the solid salt in (100 ml) of distilled water.

Add (1 ml) of sodium sulphite solution to ca. (2 ml) of silver nitrate solution.What do you observe?

Exp. 1

Observation:

White ppt. of silver sulphite.Equation:

332323 2NaNOSOAgSONa2AgNO

Dissolve the precipitate from experiment (1) in (1ml) dil. HNO3, then add (3ml) of sodium carbonate solution. What do you observe?

Exp. 2

Observation:

White ppt. of silver carbonate.

Equation:

Dissolve the precipitate obtained from exp.2 in (0.5 ml) of HNO3 and then add few drops of (Na3PO4).What do you observe?

Exp. 3

332323 2NaNOCOAgCONa2AgNO

Observation:

Yellow ppt. of silver Phosphate.

FinallyDissolve the precipitate formed from exp.3 in a few drops of HNO3. The product is the starting solution of silver nitrate.

FinallyDissolve the precipitate formed from exp.3 in a few drops of HNO3. The product is the starting solution of silver nitrate.

Equation:

343433 3NaNOPOAgPONa3AgNO

IF EXP. (I) GIVES NO PRECIPITATE THEN CARRY

OUT EXP. II

IF EXP. (I) GIVES NO PRECIPITATE THEN CARRY

OUT EXP. II

EXPERIMENT. IIEXPERIMENT. II

To (1 ml) of the unknown solution add (1 ml) of dil. HCl and (1 ml) solution of Na2S solution.What do you observe?

If canary yellowppt.

If dark brownppt. If black ppt.

If a white thenyellow, brown andfinally black ppt

This means that(Cd2+) is present.Carry out (SI - 3)

toconfirm this result

This means that(Bi3+) is present.Carry out (SI- 4)to confirm this

result.

This means that(Cu2+) is present.Carry out (SI- 5)to confirm this

result.

This means that(Hg2+) is present.Carry out (SI- 6)to confirm this

result.

Systemic Investigation of [Cd2+]

SI - 3Systemic Investigation of [Cd2+]

SI - 3

Idea of experiment:

(1) Qualitative investigation of [Cd2+] in a systemic

cycle.

(2) Preparation of different [Cd2+] compounds.

(3) Inter-conversion of [Cd2+] compounds.

Exp.1

Cadmium chloride

Cd2+

(yellow canary ppt.)Cadmium sulphide

(white ppt.)Cadmium carbonate

(white ppt.)Cadmium hydroxide

Exp.2Exp.4

Exp.3

Nitrate salt

HNO3

(SI - 3)Reagents Used:

(1) Acids:HCl.: 1:1 solution.HNO3 (Conc.).

(2) Alkali:NaOH (0.1 M solution).

(3) Salts:Sodium Carbonate.Sodium Sulphide.

Exp. 1

Add (1 ml) of sodium carbonate solution to ca. (2 ml) of the original cadmium solution.What do you observe?

Observation:

White ppt. of cadmium carbonate.

Equation:

2NaClCdCOCONaCdCl 3322

Exp. 2

Dissolve the precipitate from experiment (1) in (1 ml) dil. HCl.

Observation:

White ppt. of cadmium hydroxide.

Exp. 3

Add (3 ml) of sodium hydroxide solution.What do you observe?

Equation:

2NaClOHCdNaOH2CdCl 22

Dissolve the percipitate obtained from exp.3 in (1 ml) of HCl and then add few drops of (Na2S) solution.What do you observe?

Exp. 4

Observation:

Canary yellow ppt. of cadmium sulphide.

Equation:

2NaClCdSSNaCdCl22

FinallyDissolve the precipitate formed from exp.3 in a few drops of conc HNO3. The product is the starting solution of cadmium nitrate.

FinallyDissolve the precipitate formed from exp.3 in a few drops of conc HNO3. The product is the starting solution of cadmium nitrate.