To analyse the given salt for acidic and basic radicals. (Example No. 02)


EXPERIMENT
OBSERVATIONS
INFERENCE
1.PHYSICAL EXAM:-
a) Observe the colour of the         salt.
b) Observe the smell of the salt.

White

No specific odour

Cu2+, Mn2+, Co2+, Ni2+, Fe3+ absent.
NH4+, S2- & CH3COOH- may be absent.
2. FLAME TEST:-Prepared a paste of the salt with concentrated HCL and performed flame test.

Green flashes seen with naked eyes.

Zn2+, Mn2+ present.
3. DILUTE H2SO4 TEST:-
a) Treated a pinch of the salt with dilute H2SO4.
b) Shook a pinch of salt with water taken in a test tube.


Coulourless, odourless, gas evolved with brisk effervescence, turned lime water milky.

Salt did not dissolve.

CO32- present


Insoluble indicated.

4. CONCENTRATED H2SO4 TEST:-
This test was not performed as the salt reacted with dilute H2SO4.


No reactions

Cl-, Br-, I-, NO3-, CH3COO- and C2O42- are absent.
5. CONFIRMATORY TEST FOR CARBONATE:- Tried to dissolve the salt in water. To the salt added dilute HCl.

The salt is insoluble in water. Brisk effervescence with evolution of
colourless, odourless gas which turned lime water milky.

Insoluble carbonate indicated. Insoluble  carbonate confirmed.
6. Heated a pinch of salt with concentrated NaOH solution.
No ammonia gas evolved.
NH4+ absent.
7. PREPARATION OF ORIGINAL SOLUTION:-
a) Shook a pinch of the salt with H2O.
b) Shook a pinch of the salt in dilute HCL.


Insoluble
Clear solution obtained.

Labelled it as OS as the O.S was prepared in dil. HCl.
8. As the O.S. is prepared in dil. HCl

Group I absent (Pb2+ absent)
9. Through a part of O.S passed H2S gas.
 
No ppt. formed.

Group II absent. (Pb2+, Cu2+, As3+ absent)
10. To the remaining solution, add a pinch of solid ammonium chloride. Boiled the solution, cooled it and added excess of ammonium hydroxide solution.
 
No ppt. formed.
Group III absent
11. CONFIRMATORY TEST FOR Zn2+ ION :-Dissolved in the above ppt. formed in dilute HCL. Boiled off H2S. Divided the solution in two parts:-
a)    To one part, added NaOH solution dropwise.
b)    To another part, added potassium ferrocyanide solution.






White ppt. soluble in excess of NaOH solution.
Blush white ppt.





Zn2+ confirmed.

Zn2+ confirmed.

   Result:-              Acidic Radical CO32-                     Basic radical- Zn2+

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