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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?
- What is the formula of the white gelatinous precipitate obtained?
On addition of dilute ammonia solution to a colourless salt solution, a white gelatinous precipitate is formed which dissolves when ammonia solution is in excess. Identify the metal from Na, Al, Pb, Fe, Zn whose salt solution is used. What is the formula of the precipitate formed?
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उत्तर
(a) Zinc (Zn) metal salt solution was used.
(b) The formula of the white gelatinous precipitate is Zn(OH)2.
Concept Insight:
\[\ce{\underset{Colourless}{ZnSO4} + 2NH4OH ->\underset{White ppt.}{Zn(OH)2} + (NH4)2SO4}\]
With an excess of NH4OH the precipitate of zinc(II) hydroxide dissolves as:
\[\ce{Zn(OH)2 +\underset{In excess}{(NH4)2SO4 + 2NH4OH} ->\underset{\underset{(Colourless solution)}{Tetrammine zinc(II)Sulphate}}{[Zn(NH3)4]SO4}+ 4H2O}\]
संबंधित प्रश्न
Write the probable colour of the following salt:
Cupric salts
Write the probable colour of the following salt:
Ferrous sulphate
Name the probable cation present in each of the following solution:
Pink coloured solution
Write the colour of the following salt : Calcium salts.
One chemical test that would enable you to distinguish between the following pair of chemicals. Describe what happens with each chemical or state 'no visible reaction'.
Calcium nitrate solution and zinc nitrate solution.
Write balanced equation for the following reaction:
Chlorine and cold dilute sodium hydroxide solution.
Write the observation, and balanced equation for the following reaction:
Moist starch iodide paper is placed at the mouth of a test tube containing chlorine gas.
The questions (i) to (v) refer to the following salt solutions listed A to F:
- Copper nitrate
- Iron (II) sulphate
- Iron (III) chloride
- Lead nitrate
- Magnesium sulphate
- Zinc chloride
- Which two solutions will give a white precipitate when treated with dilute hydrochloric acid followed by barium chloride solution?
- Which two solutions will give a white precipitate when treated with dilute nitric acid followed by silver nitrate solution ?
- Which solution will give a white precipitate, when either dilute hydrochloric acid or dilute sulphuric acid is added to it?
- Which solution becomes a deep/inky blue colour when excess of ammonium hydroxide is added to it ?
- Which solution gives a white precipitate with excess ammonium hydroxide solution?
Name :
a coloured metallic oxide which dissolves in alkalis to yield colourless solutions.
| Abhishek was given a salt ‘X’ which was white in colour for analysis. On strong heating, it produced a yellow residue, a colourless gas and also a reddish-brown gas. The solution of the salt ‘X’, when tested with an excess of ammonium hydroxide, produced a chalky white insoluble precipitate. |
- Name the coloured gas that evolved when Abhishek heated the salt strongly.
- Which cation was present in the sample given to Abhishek?
- Identify the salt given to Abhishek for analysis.
