1. Preliminary Tests a) Note the colour of the salt.
Observations
Inference
(i) Blue
Cu
(ii) Bluish green
Cu or Ni
2+ 2+
2+
3+
(iii) Brown or yellowish brown
Fe or Mn
(iv) Brown or deep pink or violet
Co
(v) Light green (vi) Light pink or flesh coloured
Fe or Ni
(vii) White
2+
2+
2+
2+
2+
Mn
2+
2+
Absence of Cu , Ni 3+
2+
2+
Fe , Fe , Mn and Co 1. Note the smell of the salt by rubbing the moistened salt between the fingers.
2. Take a little of the salt on a piece of paper and place this on the palm of your hand to find whether the salt is heavy or light.
2+
+
(i) Ammoniacal smell
NH4
(ii) Smell of rotten eggs (iii) Vinegar smell
S CH3COO-
(i) It is quite heavy salt
Ba or Pb Salt
(ii) It is a light salt and a fluffy
ZnCO3 or MgCO 3
powder
or CaCO 3
2-
2+
2+
2. Dil H2SO4 Test Take a little of the sal salt (about 0.5g) in a test tube and add dil. H2S04. Warm if no reaction takes place. (a)
Gas Evolved
(i) A colourless, odourless, gas evolves with effervescence which turns lime water milky (CO2 gas)
CO3
(ii) A colourless gas having burning sulphur smell evolves which turns acidified potassium dichromate green (SO2 gas)
SO3
(iii) A colourless gas having rotten eggs smell evolves which turn lead acetate paper black H 2S gas
S
(iv) A brown gas having pungent smell evolves which turns FeSO 4 solution black (NO2 gas)
NO2
(v) No gas evolved
CO3 ,SO3 ,S ,NO2 Absent
(a) A white ppt is formed formed in the reaction mixture
Pb2+, Ba2+, Sr2+ or Ca2+ is present
2-
2-
2-
-
2-
2. Conc H 2SO4 Test
2-
2-
-
Take a little of the salt in a test-tube. Add conc H2SO4 just to soak the salt and then heat.
(i) A colourless gas having pung-gentsmell evolves whichgives white dense fumes with a rod dipped in NH 4OH (HCI gas)
Cl
(ii) A yellowish brown gas having irritating smell evolves which turns starch paper yellow (Br 2 gas)
Br
(iii) A dark violet gas evolves which turns starch paper blue (l 2 gas)
I
(iv) A reddish brown gas having pungent smell evolves which turns. FeSO 4 solution black. (NO2 gas)
NO3
(v) A colourless gas having vinegar smell evolves. [Acetic acid (CH3COOH) vapours]
CH3COO
(vi) A colourless, odourless gas which burns with a blue flame (CO gas) along with CO2 gas which turns lime water milky.
Oxalate (C2O4 )
-
-
-
-
-
2-
3.Confirmatory (or wet) Tests for Acid radicals 1. Confirmation of carbonate (a) Take a little of the salt in a test-tube and add distilled water. Shake
(i) Clear solution
(i) Soluble carbonate of +
NH4
2-
(ii) Salt is insoluble in water
Insoluble CO3
(b) Magnesium sulphate test: To the aqueous solution of soluble carbonate add MgSO4 solution
White precipitate
Soluble CO3 confirmed
(c) Phenolphthalein test: To another part of aqueous solution of soluble salt add phenolphthalein
Pink colour
Soluble CO3 confirmed
(a) Barium chloride test: To a portion of aqueous solution or soda extract add acetic acid till effervescence ceases. Then add BaCI2 solution.
A white ppt which dissolves in dil HCI with the evolution of SO 2 gas
SO3 confirmed
(b) Ferric chloride test: To a portion of aqueous extract add FeCI 3solution.
Dark red colour which changes into reddish brown ppt on boiling
SO3 confirmed
Curdy white ppt soluble in NH 4OH
Cl confirmed
Yellowish green gas evolves which bleaches moist blue litmus paper
Cl confirmed
2-
2-
2. Confirmation of sulphite
2-
2-
3. Confirmation of Chloride (a) Silver nitrate test:To aqueous solution or soda extract, add dil HNO 3 till acidic. Then add AgNO3 solution.
(b) MnO 2 test: Mix salt with MnO2 in a test tube. Then add conc. H 2SO4 and heat.
-
-
(c)Chromyl Chloride test: Mix salt with solid K2Cr 2O7 in a test tube. Then add conc H 2SO4 and heat.
Red vapours of chromyl chloride evolve which on passing through water gives yellow solution which on adding lead acetate solution gives yellow ppt
Cl confirmed
Pale yellow ppt sparingly soluble in NH4OH
Br confirmed
Yellow ppt insoluble in NH4OH
I confirmed
Dark brown or black ring is formed at the junction of the layers of the acid and the solution
NO3 confirmed
-
4. Confirmation of bromide (a )Silver nitrate test:To aqueous solution or soda extract add HN0 3till acidic.Then add AgN03 solution.
-
5. Confirmation of iodide (a) Silver nitrate test:To aqueous solution or soda extract add HN0 3 till acidic. Then add AgN03 solution.
-
6. Confirmation of nitrate
(a) Ring test: To the aqueous solution of the salt, add freshly prepared FeS0 4 solution. Shake and then add conc. H 2S04 along the sides of test-tube.
(b) Copper chips test: To a little of the salt in a test tube add copper chips (or paper Dark brown fumes evolves pellet) and then add conc.H 2S04. Heat.
-
-
NO3 confirmed
7. Confirmation of acetate
(a) Oxalic acid test: Mix a little of the salt with solid oxalic acid. Moisten it with a drop of water. Rub this paste between the fingers.
Vinegar smell
Acetate confirmed
(b) Ester test: To a little of the salt taken in a test tube add conc. H2SO4 & few drops of Pleasant fruity smell of ester ethyl alcohol. Heat
Acetate confirmed
(c) FeCI 3 test: To the aqueous solution of Blood red colour the salt add neutral FeCI 3 solution
Acetate confirmed
8. Confirmation of sulphate
(a) BaCI2 test: To a little of the solution add HCI. Heat to expel if any gas is formed. Then add BaCI2 solution.
4.Wet Tests for Basic radicals 1. Preparation of original solution (O.S.)
White ppt insoluble in HCI
2-
S04 confirmed
Take a little of the salt and try to dissolve in the following solvents one by one (i)
Distilled water - cold or hot
(ii) Dil. HCI - cold or hot (iii) Conc. HCI - cold or hot (iv) HNO3 - cold or hot Once the solvent is found out then prepare O.S. with 0.5 to 1g. of the salt Note : (i) If solvent is conc. HCI please dilute the solution with distilled water. (ii) If solvent is HNO3, evaporate the solution to dryness and dissolve in water +
2. Analysis of Group Zero (NH4 ) A colourless gas having ammonical smell is evolved which turns Nesseler’s solution reddish brown
NH4 is present
(a) White ppt
1st group is present
(b) No ppt
1st group is absent
with water and add 10 ml of water. Heat
ppt dissolves
Pb is present
(iii) Potassium chromate test: To one part
yellow ppt
Pb is confirmed
a) No ppt
Group II is absent
(a) Reddish Brown ppt
Fe is present
Sodium hydroxide test :To a little of salt add conc, solution of NaOH and Heat.
+
2+
3. Analysis of Group 1 (Pb ) (i) To the original salt solution in water add HCl
(ii) Hot water test: Filter the white ppt, wash 2+
2+
of hot aqueous solution of the salt add potassium chromate solution.
Note: If on adding HCI to aqueous solution no ppt is formed or original solution is 2+
prepared in HCI, then Pb is absent.
4. Analysis of Group II 2+
2+
34
[Pb , Cu and As ] This group salts are not in labs To the original solution add dil HCL and then pass H2S gas through a portion of this solution. If a coloured ppt is formed then pass H2S gas through the whole of the solution. 3+
3+
5. Analysis of Group III (Fe & Al ) (i) To the original solution, add conc. HNO 3 heat cool. Then add NH4CI solid. Again heat and cool. Then add NaOH till it gives smell of NH3.
3+
3+
(b) Gelatinous White ppt
Al is present
(c) No ppt
Fe and Al absent
Blood red colour
Fe confirmed
Deep blue solution
Fe confirmed
Blue ppt floating in colourless solution
Al confirmed
No ppt
IV group is absent
(a) A white ppt
Ba2+, Sr2+ or Ca2+ is present
(b) No ppt
V group is absent
A yellow ppt
Ba present
Grassy green flame through naked eye and bluish green through blue glass
Ba confirmed
Ammonium oxalate test: To the filtrate of 7(iii) add ammonium oxalate solution
A white ppt
Ca present
Flame test: Perform flame test with the white ppt of 7(v)
Brick red through naked eye
Ca confirmed
(i) Ammonium phosphate test: To the Oriqinal solution add NH 4Cl,NH4OH inslight excess and then ammonium phosphate.
A white ppt appears on scratching the sides of the test tube
Mg present
(ii) Cobalt nitrate test: Perform cobalt nitrate test with the salt
Pink mass
Mg confirmed
(a) Potassium sulphocyanide test: To one
3+
3+
3+
part add potassium sulphocyanide solution
(b) Potassium ferrocyanide test: To the
3+
second part add potassium ferrocyanide solution Lake test: To one part add HCI till the solution turns acidic. Then add 2 drops of blue litmus followed by NH4OH till it gives smell of ammonia 6. Analysis of Group IV (Ni2+, Co2+, Mn2+, Zn2+) This group salts are not in labs (i) To the solution of 5(ii), which gives smell of ammonia, pass H2S gas through a test portion 7. Analysis of Group V( Ba2+,Sr2+ & Ca2+) (i) To the rest of solution from 6(i) through which H2S gas has not been passed, add saturated ammonium carbonate solution and warm.
Potassium chromate test: To the white ppt of 7(i) add acetic acid and heat. To the warm solution add potassium chromate solution. Wash the yellow ppt with hot water & perform flame test with it.
3+
2+
2+
2+
2+
2+
8. Analysis of GroupVI (Mg ) 2+
2+
