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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
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?
Name the metal hydroxides which are insoluble in ammonium hydroxide solution.
State what do you observe when:
Ammonium hydroxide is added to iron (III) sulphate solution.
How would you distinguish between Zn2+ and Pb2+ ions, using ammonium hydroxide solution?
State what do you observe when ammonium hydroxide to Iron (III) sulphate solution.
Identify the cation of the following case:
NaOH solution when added to solution (A) gives a reddish brown precipitate
Identify the cation of the following case:
NaOH solution when added to solution (C) gives white ppt. which insoluble in excess.
Write balanced equation copper sulphate solution with ammonium hydroxide solution.
Write balanced equation:
Copper sulphate solution with ammonium hydroxide solution.
A ______ coloured precipitate is formed when ammonium hydroxide is added to a solution of ferrous chloride.
