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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?
Write the observation for the following:
Excess NH4OH is added to a substance obtained by adding hydrochloric acid in silver nitrate solution.
Identify the cation of the following case:
NaOH solution when added to solution (C) gives white ppt. which insoluble in excess.
The salt solution which does not react with ammonium hydroxide is ______.
Write balanced equation:
Copper sulphate solution with ammonium hydroxide solution.
Write balanced equation:
Copper sulphate solution with ammonium hydroxide solution.
Write a balanced equation:
Copper sulphate solution with ammonium hydroxide solution.
Rita was given an unknown salt for identification. She prepared a solution of the salt and divided it into two parts.
- To the first part of the salt solution, she added a few drops of ammonium hydroxide and obtained a reddish-brown precipitate.
- To the second part of the salt solution, she added a few drops of silver nitrate solution and obtained a white precipitate.
Name:
- The cation present and
- The anion present in the salt given for identification.
Write balanced equation:
Copper sulphate solution with ammoni um hydroxide solution.
Write balanced equation:
Copper sulphate solution with ammonium hydroxide solution.
