To analyse the given salt for acidic and basic radicals
| Experiment | Observations | Inference |
| 1. Physical examination:
(a) Noted the colour of the given salt. (b) Noted the smell of the salt. |
White No specific odour |
Cu2+, Mn2+, Co2+, Ni2+, Fe3+ absent. NH4+, S2- and CH3COO– may be absent. |
| 2. Dry heating test
Heated a pinch of the salt in a dry test tube and noted the following observations : (a) Gas evolved
(b) Sublimation
(c) Decrepitation
(d) Colour of the residue |
A reddish brown gas evolved which turned FeSO4 solution black.
No sublimate formed.
No crackling sound observed.
White |
N03- may be present.
Ammonium halides, aluminium chloride, iodide may be absent.
Lead nitrate, barium nitrate, may be absent.
Ba2+, Sr2+, Ca2+, Al3+, Mg2+, etc., may be present. |
| 3. Charcoal cavity test
Mixed a pinch of the salt with double the quantity of Na2CO3 and heated the mixture on a charcoal cavity in the reducing flame. |
White residue.
|
Ba2+, Sr2+, Ca2+, Al3+, Mg2+,
etc., may be present. |
| 4. Cobalt nitrate test
To the above white residue added a drop of cobalt nitrate solution. Heated it in oxidising flame. |
No characteristic colour.
|
Al3+, Zn2+„Mg2+, PO43-, may be absent.
|
| 5. Flame test
Prepared a paste of the salt with cone. HCl and performed flame test. |
Persistent grassy green flame
on prolonged heating. |
Ba2+ present.
|
| 6. Borax bead test
Did not perform this test since the given salt was white. |
– | Cu2+, Mn2+, Co2+, Ni2+, Fe3+ may be absent. |
| 7. Dil. sulphuric acid test
Treated a pinch of the salt with dil. H2SO4 and warmed. |
No gas evolved.
|
CO32-, S2-, SO32-, NO2– may be absent.
|
| 8. KMnO4 test
To a pinch of the salt added dil. H2SO4 and a drop of KMnO4 solution. |
Pink colour of KMnO4 was not
discharged. |
Cl–, Br–, I–, C2O42- and Fe2+ may be absent.
|
| 9. Cone, sulphuric acid test
Heated a pinch of the salt with cone, sulphuric acid and added to it a paper pellet. |
A reddish brown gas evolved which turned FeSO4 solution black. | NO3– may be present. |
| 10. Confirmatory test for ni-trate
(a) Copper chips test. Heated a pinch of the salt with cone, sulphuric acid and a few copper chips. (b) Ring test. To 2-3 ml of the salt solution, added freshly pre-pared FeSO4 solution. Then added cone, sulphuric acid along the sides of the test tube. |
Reddish brown gas evolved.
A dark brown ring formed at the junction of the two liquids. |
NO3– confirmed.
NO3– confirmed. |
| 11. Heated a pinch of salt with cone. NaOH solution | No ammonia gas evolved. | NH4+ absent. |
| 12. Preparation of Original Solution (O.S.)
Shook a pinch of the salt with water. |
Solution obtained
|
Labelled it as Original Solution (O.S.) |
| 13. To a part of the O.S. added 1-2 ml of dilute hydro-chloric acid. | No ppt. formed. | Group I absent. (Pb2+ absent) |
| 14. Through a part of the above solution, passed H2S gas. | No ppt. formed. | Group II absent (Pb2+, Cu2+, As3+, absent) |
| 15. To the remaining solution, added a pinch of solid ammonium chloride. Boiled the solution, cooled it and added excess of ammonium hydroxide solution. | No ppt. formed.
|
Fe3+, Al3+ absent
|
| 16. Through a part of the above solution, passed H2S gas. | No ppt. formed.
|
Group IV absent.
(Zn2+, Mn2+, Co2+ and Ni2+ absent) |
| 17. To the remaining ammonical solution added ammonium carbonate solution. | White ppt. formed. | Group V present.
(Ca2+, Ba2+, Sr2+ may be present) |
| 18. Confirmatory test for Ba2+ ion
Filtered the above white ppt. Dissolved the ppt. in hot dilute acetic acid. (a) Pot. chromate test. To one part of the above solution, added a few drops of pot. chromate solution. (b) Flame test. Performed flame test with the salt.
|
Yellow ppt. Persistent grassy green flame on prolonged heating.
|
Ba2+ confirmed. Ba2+ confirmed. |
Result
Acid radical : NO3–
Basic radical : Ba2+.
| Experiment | Observations | Inference |
| 1. Physical examination:
(a) Noted the colour of the given salt. (b) Noted the smell of the salt. |
White
No specific odour |
Cu2+, Mn2+, Co2+, Ni2+, Fe3+ absent. NH4+, S2- and CH3COO– may be absent. |
| 2. Dry heating test
Heated a pinch of the salt in a dry test tube and noted the following observations : (a) Gas evolved
(b) Sublimation
(c) Decrepitation
(d) Colour of the residue |
A colorless gas evolved which turned lime water milky.
No sublimate formed.
No crackling sound observed.
Yellow when hot and white when cold |
CO32- may be present.
Ammonium halides, aluminium chloride, iodide may be absent.
Lead nitrate, barium nitrate, may be absent.
Zn2+ may be present. |
| 3. Charcoal cavity test
Mixed a pinch of the salt with double the quantity of Na2CO3 and heated the mixture on a charcoal cavity in the reducing flame. |
Yellow when hot and white when cold | Zn2+ may be present. |
| 4. Cobalt nitrate test
To the above white residue added a drop of cobalt nitrate solution. Heated it in oxidising flame. |
Green Residue | Zn2+ may be pesent. |
| 5. Flame test
Prepared a paste of the salt with cone. HCl and performed flame test. |
Green flashes seen with naked eye | Zn2+ , Mn2+ may be present. |
| 6. Borax bead test
Did not perform this test since the given salt was white. |
– | Cu2+, Mn2+, Co2+, Ni2+, Fe3+ may be absent. |
| 7. Dil. sulphuric acid test
Treated a pinch of the salt with dil. H2SO4 and warmed.
Shook a pinch of salt with water taken in test tube. |
Colourless, odourless gas evolved with brisk effervescence, turned lime water milky.
Salt did not dissolve. |
CO32- present
Insoluble CO32- indicated. |
| 8. KMnO4 test
To a pinch of the salt added dil. H2SO4 and a drop of KMnO4 solution. |
Pink colour of KMnO4 was not discharged.
|
Cl–, Br–, I–, C2O42- and Fe2+ may be absent.
|
| 9. Cone, sulphuric acid test
This test was not performed as the salt reacted with dil. H2SO4. |
– | Cl–, Br–, I–, C2O42-, CH3COO– and Fe2+ may be absent. |
| 10. Confirmatory test for carbonate
Tried to dissolve the salt in water. To the salt added dil HCl |
The salt is insoluble in water.
Brisk effervescence with evolution of colourless, odourless gas which turned lime water milky. |
Insoluble carbonate.
Insoluble carbonate confirmed. |
| 11. Heated a pinch of salt with cone. NaOH solution | No ammonia gas evolved. | NH4+ absent. |
| 12. Preparation of Original Solution (O.S.)
(a) Shook a pinch of the salt with water. (b) Shook a pinch of the salt in dil. HCl. |
Insoluble Clear solution obtained |
Labelled it as O.S. As the O.S. was prepared in dil. HCl |
| 13. Through a part of O.S. passed H2S gas. | No ppt. formed. | Group I absent. (Pb2+ absent) |
| 14. To the remaining solution, added a pinch of solid ammonium chloride. Boiled the solution, cooled it and added excess of ammonium hydroxide solution. | No ppt. formed. | Group II absent (Pb2+, Cu2+, As3+, absent) |
| 15. Through a part of the above solution, passed H2S gas. | Group III absent
Fe3+, Al3+ absent |
|
| 16. Confirmatory tests for Zn2+ ion
Dissolved the above dull white ppt. in dil HCl. Boiled off H2S. Divided the solution into two parts. (a) To one part added NaOH solution dropwise. (b) To another part, added potassium ferrocyanide solution. |
Dull White ppt. formed.
White ppt. soluble in excess of NaOH solution. Bluish white ppt. |
Group IV absent.
(Zn2+ present)
Zn2+ confirmed. Zn2+ confirmed.
|
Result
Acid radical : CO32-
Basic radical : Zn2+
Chemistry Lab ManualNCERT Solutions Class 11 Chemistry Sample Papers