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प्रश्न
You are provided with PbCO3, ZnCO3 and CaCO3. How will you identify these cations?
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उत्तर
By use of Ammonium hydroxide we can identify the ions PbCO3, ZnCO3 and CaCO3 as :
(i) \[\ce{PbCO3 + 2NH4OH -> Pb(OH)2 v + 2NH4NO3}\]
Pb(OH)2 forms white precipitate which are insoluble in excess ammonium hydroxide.
(ii) \[\ce{ZnCO3 + NH4OH -> Zn(OH)2 v + 2Na2CO3}\]
Zn(OH)2 forms white gelatinous precipitate which are soluble in excess ammonium hydroxide.
(iii) \[\ce{CaCO3 + NH4OH -> Ca(OH)2 + 2Na2CO3}\]
No precipitation of Ca(OH)2 occurs even with addition of excess of NH4OH. Because the concentration of hydroxide ion from ammonium hydroxide is so low that it cannot precipitate the hydroxide of calcium.
Concept Insight : Some precipitated metallic hydroxides by ammonium hydroxide become soluble hydroxides when treated with excess of ammonium hydroxide due to the formation of a soluble complex salt in the presence of excess of ammonium hydroxide.
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संबंधित प्रश्न
What happens when ammonia solution is added first dropwise and then in excess to the following solution:
ZnSO4
Write a balanced equation for this reaction.
On adding dilute ammonia solution to a colourless solution of a salt, a white gelatinous precipitate appears. This precipitate however dissolves on addition of excess of ammonia solution. Identify (choose from Na, Al, Zn, Pb, Fe)
What is the formula of the white gelatinous precipitate obtained?
Fill in the blank.
The salt which will not react with NH4OH solution ______[ZnCl2, CuCl2 / NH4Cl/ FeCl2]
State what do you observe when ammonium hydroxide to Iron (III) sulphate solution.
How would you distinguish between Zn2+ and Pb2+ using ammonium hydroxide solution?
Write the observation for the following:
NaOH is added drop-wise till in excess to a solution of zinc sulphate.
______ is a white precipitate that is soluble in excess of Ammonium hydroxide solution.
Identify the cation in the following case:
Ammonium hydroxide solution when added to Solution B gives a white precipitate which does not dissolve in excess of ammonium hydroxide solution.
Write a balanced equation:
Copper sulphate solution with ammonium hydroxide solution.
Write balanced equation:
Copper sulphate solution with ammoni um hydroxide solution.
