June 21, 2012

GENERAL PROCEDURE for THE SYSTEMATIC ANALYSIS OF A SIMPLE SALT

I. PRELIMINARY TESTS
S. No.
EXPERIMENT
OBSERVATION
INFERENCE
1
SOLUBILITY
A little of the salt is shaken with water.
1) Soluble
1) May be Sulphate, Nitrate, Chloride or Ammonium Carbonate.
2) Insoluble
2) May be Carbonate or Sulphide.
2
ACTION OF HEAT:
A small amount of the salt is heated gently   in   a dry test tube.
1) Colourless, odourless gas turning limewater milky.
1) May be Carbonate.
2) Decripitation occurs with evolution of reddish brown gas.
2) May be Nitrate.                          
3) Salt sublimes with evolution of pungent smelling gas giving dense white fumes with a glass rod dipped in conc HCl.                               
3) May be Ammonium.
4) The white salt turns yellow on heating.
4) May be Zinc.


5) No characteristic change.
5) Absence of Carbonate, Nitrate,    Ammonium and Zinc.
3
FLAME TEST:
A small amount of the salt is made into a paste with conc. HCl in a watch glass and introduced into the non-luminous part of the Bunsen flame.
1) Bluish colour flame.
1)  Presence of Copper.

2) Brick red flame.
2) Presence of Calcium.
          
3) Grassy green flame.
3) Presence of Barium.

4)  No characteristic coloured flame.
4) Absence of Copper, Calcium and Barium.
4
ASH TEST:
A filter paper is soaked into a paste of the salt with conc. HCl and Cobalt Nitrate solution in a watch glass and burnt.
1) Green ash.
1) Presence of Zinc.
2) Blue ash.
2) Presence of Aluminium.
3) Pink ash.                 
3) Presence of Magnesium.
4) No characteristic coloured ash.
4) Absence of Zinc, Aluminium and Magnesium.

II. TESTS FOR ACID RADICALS
5
ACTION OF DIL HCl
To a small amount of the salt dilute HCl is added.
1) Brisk effervescence of colourless, odourless gas turning lime water milky.
1) Carbonate is confirmed.
2) Rotten egg smelling gas turning lead acetate paper black.
2) Sulphide is confirmed.
3) No characteristic change.
3) Absence of Sulphide / Carbonate.
6
COPPER TURNINGS TEST:
A small amount of the salt is heated with Copper Turnings and a few drops of conc. Sulphuric acid.
1) Reddish brown gas is evolved.
1) Presence of Nitrate.

2) No reddish brown gas is evolved.
2) Absence of Nitrate.
7
CHROMYL CHLORIDE TEST:
To a small amount of the substance a pinch of Potassium Dichromate is added and heated with few drops of conc. Sulphuric acid.
1) Red orange vapours evolved are passed through water to get a yellow solution, which on adding lead acetate forms a yellow precipitate.
1) Chloride is confirmed.







2) No Red orange vapours.
2) Absence of chloride.

1) Pungent smelling gas forming dense white fumes with a glass rod dipped in conc. HCl and also turns litmus paper blue.
1) Presence of Ammonium.


 2) No pungent smelling gas.
2) Absence of Ammonium.
8
ACTION OF NaOH:
A small amount of the substance is heated with Sodium Hydroxide.
1) Pungent smelling gas forming dense white fumes with a glass rod dipped in conc. HCl and also turns litmus paper blue.
1) Presence of Ammonium.
2) No pungent smelling gas.
2) Absence of Ammonium.

III. TESTS WITH SODIUM CARBONATE EXTRACT
9. PREPARATION OF SODIUM CARBONATE EXTRACT:
A small amount of salt is mixed with twice the amount of sodium carbonate and 20ml of distilled water is added, boiled for 10 minutes, cooled and filtered. The filtrate is called “SODIUM CARBONATE EXTRACT”.
S. No
EXPERIMENT
OBSERVATION
INFERENCE
10
BARIUM CHLORIDE TEST:
To a few drops of the extract, dilute Hydrochloric Acid is added until the effervescence ceases and 2ml of Barium chloride solution is added.
1) A white precipitate, insoluble in conc. HCl.
1) Sulphate is confirmed. 
2) No white precipitate.
2) Absence of Sulphate
11
SILVER NITRATE TEST:
To a few drops of the extract dilute Nitric Acid is added until the effervescence ceases and 2ml of Silver Nitrate solution is added.
1) A curdy white precipitate, soluble in excess of ammonium hydroxide.
1) Presence of Chloride.
2) A black precipitate.
2) Presence of Sulphide.
3) No precipitate.
3) Absence of chloride/ sulphide.
12
BROWN RING TEST:
To a few drops of extract dilute Sulphuric acid is added until the effervescence ceases, then freshly prepared.
1) Brown ring is formed at the junction of the two layers.
1) Nitrate is confirmed.

2) No brown ring.
2) Absence of Nitrate.

IV .IDENTIFICATION OF THE BASIC RADICALS
13. PREPARATION OF ORIGINAL SOLUTION:
The original solution is prepared by dissolving the salt in
Water  (When the salt is water soluble)
#  Dil. HCl   (When the salt is water insoluble)
                                         Hot mixture of dil. HCl + dil. HNO3 (When the salt is sulphide)
14. GROUP IDENTIFICATION
S. No
EXPERIMENT
OBSERVATION
INFERENCE
1
To a few drops of the original solution 2ml of dilute HCl acid is added.
1) White precipitate.
1)  Presence of First Group. (Lead).
2) No characteristic precipitate.
2) Absence of First Group (Lead).
2
To a few drops of the original solution 2ml of dilute HCl acid and H2S gas is passed.
1) Black precipitate.
1)  Presence of Second   Group (Copper).
2) No characteristic precipitate.
2) Absence of Second Group (Copper).
3
To a few drops of the original solution 1ml NH4Cl and 2ml NH4OH solutions are added.
1) Gelatinous white precipitate.
1)  Presence of Third Group (Aluminium).
2) No characteristic precipitate.
2) Absence of Third Group (Aluminium / Ferric).
4
To a few drops of the original solution 1ml NH4Cl and 2ml NH4OH solutions are added and H2S gas is passed.
1) Dirty white precipitate.
1)  Presence of Fourth Group (Zinc).
2) No characteristic precipitate.
2) Absence of Fourth Group (Zinc).
5
To a few drops of the original solution 1ml NH4Cl, 2ml NH4OH and 2ml (NH4)2CO3  solutions are added.
1) White precipitate.
1) Presence of Fifth Group (Calcium / Barium).
2) No characteristic precipitate.
2) Absence of Fifth Group (Calcium / Barium).
6
To a few drops of the original solution 1ml NH4Cl, 2ml NH4OH and 2ml Di Sodium Hydrogen Phosphate are added.
1) White precipitate.
1) Presence of Sixth Group (Magnesium).

2) No characteristic precipitate.
2) Absence of Sixth Group (Magnesium).

V .CONFIRMATORY TESTS FOR BASIC RADICALS
S. No
EXPERIMENT
OBSERVATION
INFERENCE
AMMONIUM
1
Original solution + Sodium Hydroxide + Nessler’s reagent.
Reddish brown precipitate.
Ammonium is confirmed.

First group  -  LEAD
1
Original solution + Potassium Chromate.
Yellow precipitate.
Lead is confirmed.
2
Original solution +   Potassium Iodide.
Yellow precipitate soluble in hot water which reappears as golden yellow spangles on cooling.
Lead is confirmed.

Third group - ALUMINIUM
1
Original solution + Sodium Hydroxide in drops to excess.
White precipitate soluble in excess of sodium hydroxide.
Aluminium is confirmed.
2
Original solution + Ammonium Hydroxide + Aluminon reagent.
A bright red lake.
Aluminium is confirmed.
Fourth group - ZINC
1
Original solution + Sodium Hydroxide
White precipitate soluble in excess of sodium hydroxide.
Zinc is confirmed.
2
Original solution + Potassium Ferro cyanide.
White precipitate soluble in excess of sodium hydroxide & insoluble in dilute acid.
Zinc is 
confirmed.
Fifth group - CALCIUM
1
Original solution + Potassium Chromate.
No precipitate.
Calcium is confirmed.
2
Original solution + Ammonium Hydroxide + Ammonium Oxalate.
White precipitate insoluble in acetic acid.
Calcium is confirmed.
Fifth group - BARIUM
1
Original solution + Potassium Chromate.
Yellow precipitate, soluble in acid.
Barium is confirmed.
2
Original solution + Dilute Sulphuric Acid.
White precipitate insoluble in acetic acid.
Barium is confirmed.
Sixth group - MAGNESIUM
1
Original solution + Sodium Hydroxide.
White precipitate, insoluble in excess of sodium hydroxide.
Magnesium is confirmed.
2
Original solution +   Magneson reagent.
Blue precipitate.
Magnesium is confirmed.

RESULT

                The given simple salt contains
1. Basic Radical           : __________________
2. Acid Radical             : __________________

8 comments:

  1. u could have added some more.....

    ReplyDelete
  2. can put some specific salt procedure

    ReplyDelete
  3. lead acetate test missing

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  4. Ash test is done with concentrated nitric acid not hydrochloric acid

    ReplyDelete
  5. why there is no confirmative test for group2 copper

    ReplyDelete