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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)
Which metal salt solution was used?
Name the method used for preparation of the following salt from the list given below:
Zinc ion and Lead ion.
Three test tubes contain calcium nitrate solution, zinc nitrate solution and lead nitrate solution.Describe the effect of Adding ammonium hydroxide to each portion in turn till it is in excess.
Write the observation, and balanced equation for the following reaction:
Ammonium hydroxide is added first in a small quantity, and then in excess, to a solution of copper sulphate.
State two relevant observations of the following:
Ammonium hydroxide solution is added to zinc nitrate solution in minimum quantities and then in excess.
Write balanced equation:
Copper sulphate solution with ammonium hydroxide solution.
Write balanced equation:
Copper sulphate solution with ammonium hydroxide solution.
______ is a white precipitate that is soluble in excess of Ammonium hydroxide solution.
The metal hydroxide which reacts with both acids and alkalis to form salt and water is ______.
Write balanced equation:
Copper sulphate solution with ammonium hydroxide solution.
