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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
Name the metal hydroxides which are soluble in ammonium hydroxide solution.
Using ammonium hydroxide, how would you distinguish between the following pair of ions in solution?
Ferrous ion and Ferric ion.
Name the method used for preparation of the following salt from the list given below:
Zinc ion and Lead ion.
Distinguish between the given pair of compounds using the test given within brackets:
A lead salt and a zinc salt (using excess ammonium hydroxide)
State two relevant observation of the following:
Ammonium hydroxide solution is added to copper (II) nitrate solution in small quantities and then in excess
State two relevant observations of the following:
Ammonium hydroxide solution is added to zinc nitrate solution in minimum quantities and then in excess.
Write the observation for the following:
NaOH is added drop-wise till in excess to a solution of zinc sulphate.
Write the observation for the following :
NH4OH is added first in a small quantity and then in excess to a solution of copper sulphate.
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.
