Chemistry
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 precipitate (soluble or insoluble) in (vi) to (x).
| Aqueous salt solution | Colour of precipitate when NaOH is added in a small quantity | Nature of precipitate (soluble or insoluble) when NaOH is added in excess |
|---|---|---|
| Copper (II) sulphate | (i) | (vi) |
| Zinc nitrate | (ii) | (vii) |
| Lead nitrate | (iii) | (viii) |
| Calcium chloride | (iv) | (ix) |
| Iron (III) sulphate | (v) | (x) |
Answer
| Aqueous salt solution | Colour of precipitate when NaOH is added in a small quantity | Nature of precipitate (soluble or insoluble) when NaOH is added in excess |
|---|---|---|
| Copper (II) sulphate | (i) Pale blue | (vi) Insoluble |
| Zinc nitrate | (ii) White gelatinous | (vii) Soluble |
| Lead nitrate | (iii) White chalky | (viii) Soluble |
| Calcium chloride | (iv) White curdy | (ix) Insoluble |
| Iron (III) sulphate | (v) Reddish brown | (x) Insoluble |
Related Questions
Use the information given in (a) to (h) to identify the substances P to W selecting your answers from the given list.
List Calcium Oxygen Copper (II) oxide Carbon Calcium hydroxide Copper (II) nitrate Lead (II) oxide Hydrogen chloride Chlorine Lead (II) nitrate Calcium oxide Ammonium chloride (a) P is a white solid. When heated produces white fumes (sublime).
(b) P and R on warming produce an alkaline gas.
(c) On adding water to T, heat is evolved and R is formed.
(d) Q burns brightly in air to form T.
(e) When S is heated, it gives off brown fumes and leaves a black residue of U.
(f) A solution of S is formed by warming U with dilute nitric acid.
(g) V is a gaseous non-metallic element that reacts with hydrogen to form W.
(h) A solution of W will neutralise the solution of R.
Copy and complete the following table which refers to the action of heat on some carbonates :
Carbonate Colour of residue on cooling Zinc carbonate Lead carbonate Copper carbonate Mention the colour change when following indicators are added:
Solution Acids Alkalies (a) Alkaline phenolphthalein solution, (b) Methyl orange solution, (c) Neutral litmus solution (a) Select the correct answer from A, B, C and D.
A. Nitroso iron (II) sulphate
B. Iron (III) chloride
C. Chromium sulphate
D. Lead (II) chloride.
(i) The compound which is responsible for the green colour formed when SO2 is bubbled through acidified potassium dichromate solution.
(ii) Compound responsible for brown ring.