Chemistry
State your observations when:
(a) lead nitrate solution and sodium chloride solution are mixed.
(b) zinc chloride solution, zinc nitrate solution and zinc sulphate solutions are added individually to
(i) barium chloride solution,
(ii) lead nitrate solution.
(c) Decomposition of bicarbonates by dil. H2SO4
2NaHCO3 + H2SO4 ⟶ Na2SO4 + 2H2O + 2CO2
2KHCO3 + H2SO4 ⟶ K2SO4 + 2H2O + 2CO2
(d) Zinc carbonate is heated strongly.
(e) a piece of moist blue litmus paper is introduced in a jar of chlorine.
(f) paper soaked in potassium permanganate solution — is introduced in each case into a jar of sulphur dioxide.
(g) When moist starch iodide paper is introduced into chlorine gas.
Practical Chemistry
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Answer
(a) When lead nitrate solution is mixed with sodium chloride solution, a white precipitate of lead chloride is seen and the soluble salt sodium nitrate is formed.
2NaCl + Pb(NO3)2 ⟶ 2Na(NO3)2 + PbCl2↓
Precipitate of lead chloride and sodium nitrate are formed.
(b)
| Zinc Chloride Solution | Zinc Nitrate Solution | Zinc Sulphate Solution | |
|---|---|---|---|
| Barium Chloride Solution | No reaction | No ppt. observed | White ppt. is obtained which is insoluble in mineral acid. |
| Lead Nitrate Solution | White ppt. is obtained | No reaction | No ppt. observed |
(c) Carbon dioxide gas is evolved with brisk effervescence which turns blue litmus red and extinguishes a burning wooden splinter.
(d) When zinc carbonate is strongly heated, the light amorphous white solid, changes to pale yellow colour.
ZnCO3 ZnO + CO2
(e) Moist blue litmus turns red and then may eventually get bleached.
(f) Sulphur dioxide turns potassium permanganate from pink to clear colourless.
2KMnO4 + 2H2O + 5SO2 ⟶ K2SO4 + 2MnSO4 + 2H2SO4
(g) Chlorine gas turns moist starch iodide paper blue black.
Cl2 + 2KI ⟶ 2KCl + I2
[Starch + I2 ⟶ blue black colour]
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Related Questions
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 solution?
Salts A, B, C, D and E undergo reactions (i) to (v) respectively. Identify the anion present in these salts on the basis of these reactions.
(a) When silver nitrate solution is added to a solution of A, a white precipitate, insoluble in dilute nitric acid, is formed.
(b) Addition of dilute hydrochloric acid to B produces a gas which turns lead acetate paper black.
(c) When a freshly prepared solution of ferrous sulphate is added to a solution of C and concentrated sulphuric acid is gently poured from the side of the test-tube, a brown ring is formed.
(d) When dilute sulphuric acid is added to D, a gas is produced which turns acidified potassium dichromate solution from orange to green.
(e) Addition of dilute hydrochloric acid to E produces an effervescence. The gas produced turns lime water milky but does not affect acidified potassium dichromate solution.
Complete the following table and write your observations.
Hydrogen sulphide Ammonia Sulphur dioxide Hydrogen chloride Shake the gas with red litmus solution Shake the gas with blue litmus solution Apply a burning splint to the gas Identify the anion present in the following compounds :
(i) Compound X on heating with copper turnings and conc. sulphuric acid liberates a reddish brown gas.
(ii) When a solution of compound Y is treated with silver nitrate solution a white precipitate is obtained which is soluble in excess of ammonium hydroxide solution.
(iii) Compound Z which on reacting with dilute sulphuric acid liberates a gas which turns lime water milky, but the gas has no effect on acidified potassium dichromate solution.
(iv) Compound L on reacting with barium chloride solution gives a white precipitate insoluble in dilute hydrochloric acid or dilute nitric acid.