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 |
Cu 2+ , Mn 2+ , Co 2+ , Ni 2+ , Fe 3+ absent. NH 4 + , S 2- and CH 3 COO – 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 FeSO 4 solution black.
No sublimate formed.
No crackling sound observed.
White |
N0 3- may be present.
Ammonium halides, aluminium chloride, iodide may be absent.
Lead nitrate, barium nitrate, may be absent.
Ba 2+ , Sr 2+ , Ca 2+ , Al 3+ , Mg 2+ , etc., may be present. |
|
3. Charcoal cavity test
Mixed a pinch of the salt with double the quantity of Na 2 CO 3 and heated the mixture on a charcoal cavity in the reducing flame. |
White residue.
|
Ba
2+
, Sr
2+
, Ca
2+
, Al
3+
, Mg
2+
,
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.
|
Al
3+
, Zn
2+
„Mg
2+
, PO
4
3-
, 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. |
Ba
2+
present.
|
|
6. Borax bead test
Did not perform this test since the given salt was white. |
– | Cu 2+ , Mn 2+ , Co 2+ , Ni 2+ , Fe 3+ may be absent. |
|
7. Dil. sulphuric acid test
Treated a pinch of the salt with dil. H 2 SO 4 and warmed. |
No gas evolved.
|
CO
3
2-
, S
2-
, SO
3
2-
, NO
2
–
may be absent.
|
|
8. KMnO
4
test
To a pinch of the salt added dil. H 2 SO 4 and a drop of KMnO 4 solution. |
Pink colour of KMnO
4
was not
discharged. |
Cl
–
, Br
–
, I
–
, C
2
O
4
2-
and Fe
2+
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 FeSO 4 solution black. | NO 3 – 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 FeSO 4 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. |
NO
3
–
confirmed.
NO 3 – confirmed. |
| 11. Heated a pinch of salt with cone. NaOH solution | No ammonia gas evolved. | NH 4 + 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. (Pb 2+ absent) |
| 14. Through a part of the above solution, passed H 2 S gas. | No ppt. formed. | Group II absent (Pb 2+ , Cu 2+ , As 3+ , 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.
|
Fe
3+
, Al
3+
absent
|
| 16. Through a part of the above solution, passed H 2 S gas. |
No ppt. formed.
|
Group IV absent.
(Zn 2+ , Mn 2+ , Co 2+ and Ni 2+ absent) |
| 17. To the remaining ammonical solution added ammonium carbonate solution. | White ppt. formed. |
Group V present.
(Ca 2+ , Ba 2+ , Sr 2+ may be present) |
|
18. Confirmatory test for Ba
2+
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.
|
Ba 2+ confirmed. Ba 2+ confirmed. |
Result
Acid radical : NO
3
–
Basic radical : Ba
2+
.
| 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 |
Cu 2+ , Mn 2+ , Co 2+ , Ni 2+ , Fe 3+ absent. NH 4 + , S 2- and CH 3 COO – 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 |
CO 3 2- may be present.
Ammonium halides, aluminium chloride, iodide may be absent.
Lead nitrate, barium nitrate, may be absent.
Zn 2+ may be present. |
|
3. Charcoal cavity test
Mixed a pinch of the salt with double the quantity of Na 2 CO 3 and heated the mixture on a charcoal cavity in the reducing flame. |
Yellow when hot and white when cold | Zn 2+ 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 | Zn 2+ 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 | Zn 2+ , Mn 2+ may be present. |
|
6. Borax bead test
Did not perform this test since the given salt was white. |
– | Cu 2+ , Mn 2+ , Co 2+ , Ni 2+ , Fe 3+ may be absent. |
|
7. Dil. sulphuric acid test
Treated a pinch of the salt with dil. H 2 SO 4 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. |
CO 3 2- present
Insoluble CO 3 2- indicated. |
|
8. KMnO
4
test
To a pinch of the salt added dil. H 2 SO 4 and a drop of KMnO 4 solution. |
Pink colour of KMnO
4
was not discharged.
|
Cl
–
, Br
–
, I
–
, C
2
O
4
2-
and Fe
2+
may be absent.
|
|
9. Cone, sulphuric acid test
This test was not performed as the salt reacted with dil. H 2 SO 4 . |
– | Cl – , Br – , I – , C 2 O 4 2- , CH 3 COO – and Fe 2+ 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. | NH 4 + 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. (Pb 2+ 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 (Pb 2+ , Cu 2+ , As 3+ , absent) |
| 15. Through a part of the above solution, passed H 2 S gas. |
Group III absent
Fe 3+ , Al 3+ absent |
|
|
16. Confirmatory tests for Zn
2+
ion
Dissolved the above dull white ppt. in dil HCl. Boiled off H 2 S. 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.
(Zn 2+ present)
Zn 2+ confirmed. Zn 2+ confirmed.
|
Result
Acid radical : CO
3
2-
Basic radical : Zn
2+
Chemistry Lab Manual NCERT Solutions Class 11 Chemistry Sample Papers
