what is the principle of blue lake test? which ion is confirmed by this test?
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Blue lake test:
To the mixture given,add water, then add ammonium chloride followed by ammonium hydroxide.
white ppt is formed which comfirms Al3+.
Thisppt is dissolved in HCl. colourless solution is obtained.
Al(OH)3 + 3HCl → AlCl3 + 3H2O (dissolution)
Then 2 drops of blue litmus solution is added. Red colour is obtained. and ammonium hydroxide is added to make the solutionalkaline. so that ammonium hydroxide is formed
As soon as the solution becomes alkaline, blue floating precipitate is obtained.
AlCl3 + 3NH4OH → 3NH4Cl + Al(OH)3
Then the blue litmus solution is adsorbed on this aluminium hydroxide.
This is the Principle for this test, Aluminium hydroxide is a good adsorbent, and therefore it adsorbs the blue litmus solution and gives this blue lake test.
To the mixture given,add water, then add ammonium chloride followed by ammonium hydroxide.
white ppt is formed which comfirms Al3+.
Thisppt is dissolved in HCl. colourless solution is obtained.
Al(OH)3 + 3HCl → AlCl3 + 3H2O (dissolution)
Then 2 drops of blue litmus solution is added. Red colour is obtained. and ammonium hydroxide is added to make the solutionalkaline. so that ammonium hydroxide is formed
As soon as the solution becomes alkaline, blue floating precipitate is obtained.
AlCl3 + 3NH4OH → 3NH4Cl + Al(OH)3
Then the blue litmus solution is adsorbed on this aluminium hydroxide.
This is the Principle for this test, Aluminium hydroxide is a good adsorbent, and therefore it adsorbs the blue litmus solution and gives this blue lake test.
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