Advertisements
Advertisements
Question
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
Solution
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
RELATED QUESTIONS
_____________ (AgCl / PbCl2), a white precipitate is soluble in excess NH4OH
Choose the correct answer from the options given below :
Sodium zincate (Na2ZnO2) is
You are given a mixture of precipitated copper hydroxide and zinc hydroxide. Name a solvent which will dissolve:
Only zinc hydroxide
What will you observe when barium chloride solution is added to iron(II) sulphate solution.
How will the action of dilute hydrochloric acid on sodium carbonate and sodium sulphite enables you to distinguish between these two compounds?
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 |
State the colour of the residue formed when nitrate of calcium is strongly heated.
What do you understand by amphoteric oxide?
Give the balanced equations for the reaction with two different amphoteric oxides with a caustic alkali.
Write a balanced equation for the following conversion:
\[\ce{CuSO4 ->[A]Cu(OH)2 ->[B] [Cu(NH3)4]SO4}\]
