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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
What do you understand by the following:
Analysis
What do you understand by the following:
Qualitative analysis
What do you understand by the following:
Reagent
From the list given below, select the word(s) required to complete the blanks (i) to (v) in the following passage:
Note : words chosen from the list are to be used only once. Write only the answers. Do not copy the passage.
[reddish brown, ammonium, nitrogen dioxide, hydroxyl, dirty green, ammonia, acidic, alkaline]
Nitrogen and hydrogen combine in the presence of a catalyst to give (i) ______ gas. When the above mentioned gas is passed through water it forms a solution which will be (ii) ______ in nature and the solution contains (iii) ______ ions and (iv) ______ ions. The above solution when added to iron (II) sulphate solution gives a (v) ______ coloured precipitate of iron (II) hydroxide.
Fill in the blank.
Potassium sulphite on reacting with hydrochloric acid releases ________
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) |
Write balanced equation for a metal that evolves a gas which burns with a pop sound when boiled with alkali solutions.
Write balanced equation for a metal that evolves a gas which burns with a pop sound when boiled with alkali solutions.
Write balanced equation for a coloured metallic oxide which dissolves in alkalis to yield colourless solutions.
Write balanced equation for a metal that evolves a gas which burns with a pop sound when boiled with alkali solutions.
