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प्रश्न
You are provided with two reagent bottles marked A and B. One of which contains NH4OH solution and the other contains NaOH solution. How will you identify them by a chemical test?
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उत्तर
Reagent bottles A and B can identified by using calcium salts such as Ca(NO3)2.
When NaOH is added to Ca(NO3)2, Ca(OH)2 precipitates as a white precipitate that is sparingly soluble in excess of NaOH.
\[\ce{Ca(NO3)2 + 2NaOH -> Ca(OH)2 + 2NaNO3}\]
whereas, on addition of NH4OH to calcium salts, no precipitation of Ca(OH)2 occurs even with an excess of NH4OH because the concentration of OH−ions from the ionization of NH4OH is so low that it cannot precipitate the calcium hydroxide.
So the reagent bottle which gives white precipitate is NaOH and the other is NH4OH.
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संबंधित प्रश्न
Name a white, insoluble oxide that dissolves when fused with caustic soda or caustic potash.
What do you understand by the following:
Analysis
What do you understand by the following:
Qualitative analysis
What do you understand by the following:
Precipitation
State what do you observe when:
Sulphur burns.
Sodium hydroxide solution is added first in a small quantity, then in excess to the aqueous salt solution of copper (II) sulphate, zinc nitrate, lead nitrate, calcium chloride and iron (III) sulphate. Copy of the following table and write the colour of the precipitate in (i) to (v) and the nature of the precipitate (soluble or insoluble) in (vi) to (x).
|
Aqueous salt solution |
Colour of the precipitate when NaOH is added in small quantity |
Nature of the(soluble or insoluble) when NaOH is added in excess |
|
copper (II) sulphate zinc nitrate lead nitrate calcium chloride Iron (III) sulphate |
(i) (ii) (iii) (iv) (v) |
(vi) (vii) (viii) (ix) (x) |
The salt which in solution gives a pale green precipitate with sodium hydroxide solution and a white precipitate with barium chloride solution is ______.
Write balanced equation for a coloured metallic oxide which dissolves in alkalis to yield colourless solutions.
Write balanced equations for a coloured metallic oxide which dissolves in alkalis to yield colourless solutions.
Write balanced equation for a coloured metallic oxide which dissolves in alkalis to yield colourless solutions.
