Advertisements
Advertisements
प्रश्न
You are given three white powders-calcium carbonate, lead carbonate and zinc carbonate. Describe the tests you would carry out in solution, to identify the metal ion in each of the above compounds. Indicate clearly how you would prepare the solutions for the tests.
Advertisements
उत्तर
The solutions for the tests will be prepared by dissolving the given powders separately in water.
(i) Solution of Calcium carbonate:
Calcium carbonate is CaCO3 and contains Ca2+ ions. Sodium hydroxide solution NaOH can be used to identify Ca2+ since its addition to calcium carbonate solution will give white precipitates of Ca(OH)2 which are sparingly soluble in excess of NaOH.
(ii) Solution of Lead carbonate:
Lead carbonate is PbCO3 and contains Pb2+ ions. Ammonium hydroxide solution NH4OH can be used to identify Pb2+ since its addition to lead carbonate solution will give white precipitates of Pb(OH)2 which are insoluble in excess of NH4OH.
(iii) Solution of Zinc carbonate:
Zinc carbonate is ZnCO3 and contains Zn2+ ions. Sodium hydroxide solution NaOH can be used to identify Zn2+ since its addition to zinc carbonate solution will give white gelatinous precipitates of Zn(OH)2 which are soluble in excess of NaOH.
APPEARS IN
संबंधित प्रश्न
Identify the salts P and Q from the observations given below:
On performing the flame test salt P produces a lilac coloured flame and its solution gives a white precipitate with silver nitrate solution, which is soluble in Ammonium hydroxide solution.
_____________ (AgCl / PbCl2), a white precipitate is soluble in excess NH4OH
You are given a mixture of precipitated copper hydroxide and zinc hydroxide. Name a solvent which will dissolve:
Both copper hydroxide and zinc hydroxide
Sodium hydroxide solution is added first in a small quantity, then in excess to the aqueous salt solutions of copper (II) sulphate, zinc nitrate, lead nitrate, calcium chloride and iron (III) sulphate. Copy the following table and write the colour of the precipitate in (i) to (v) and the nature of the precipiatate (soluble or insoluble) in (vi) to (x)
| Aqueous salt Solution | Colour of Participitate when NaOH is added in a samll quantity | Nature of precipitate(soluble or insoluble) when NaOH added in excess |
| Copper (II) Solution | ||
| Zinc nitrate | ||
| Lead nitrate | ||
| Calcium chloride | ||
| Iron(III) sulphate |
The questions (i) to (v) refer to the following salt solutions listed A to F :
A. Copper nitrate
B. Iron (II) sulphate
C. Iron (III) chloride
D. Lead nitrate
E. Magnesium sulphate
F. Zinc chloride
(i) Which two solutions will give a white precipitate when treated with dilute hydrochloric acid followed by barium chloride solution/
(ii) Which two solutions will give a white precipitate when treated with dilute nitric acid followed by silver nitrate solution?
(iii) Which solution will give a white precipitate when either dilute hydrochloric acid or dilute sulphuric acid is added to it?
(iv) Which solution becomes a deep/inky blue colour when excess of ammonium hydroxide is added to it?
(v) Which solution gives a white precipitate with excess ammonium hydroxide?
Give the balanced equations for the reaction with two different amphoteric oxides with a caustic alkali.
Name the products formed when the reaction with two different amphoteric oxides with a caustic alkali.
Write a balanced equation for the following conversion:
\[\ce{ZnSO4 ->[A]Zn(OH)2->[B]Na2ZnO2}\]
When an ammonium hydroxide solution is added to solution B, a pale blue precipitate is formed. This pale blue precipitate dissolves in excess ammonium hydroxide giving an inky blue solution. What is the cation present in solution B?
Write balanced equations for a coloured metallic oxide which dissolves in alkalis to yield colourless solutions.
