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Periodic Classification of Elements
The reaction between iron and copper sulphate is a displacement reaction.
Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)
Here, iron displaces copper from its solution of copper sulphate.
Illustration: Take two test tubes marked as (A) and (B). Add about 10 ml. copper sulphate in each test tube. Now suspend two clean iron nails in tube (B) with the help of a thread [Fig. 1.2(a)], After 20 minutes, take out the iron nails from tube (B). Compare the intensity of the blue colour of copper sulphate solutions in test tubes (A) and (B) [Fig. 1.2 (b)]. It will be observed
Fig. 1.2. (a) Iron nails dipped in copper sulphate solution (b) Iron nails and copper sulphate solutions compared before (A) and after the experiment (B).
that blue colour of copper sulphate fades in test tube (B) because Cu2+ ions are removed from solution which is deposited on iron nails which then appears brownish. This is due to fine deposition of copper on iron nails.
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What information is available from the following equation:
CaCO3 + 2HCl→ CaCl2 + H2O+ CO2
Write and balance the following equations presented to you as written statements:
(i) Magnesium carbonate plus hydrochloric acid produces magnesium chloride plus water plus carbon dioxide gas.
(ii) Aluminium plus chlorine gas produces aluminium trichloride.
(iii) Nitrogen plus hydrogen produces ammonia.
(iv) Calcium plus sulphur produces calcium sulphide.
(v) Magnesium burns in CO2 to form magnesium oxide and carbon.
Complete and balance the following equations:
(i) NaOH +................→ Na2SO4 + H2O
(ii) Ca(OH)2 +................ → CaCO3 + H2O
(iii) ................ + HCl(aq) → MgCl2(aq) +.................
(iv) ................ + Na2SO4(aq) → BaSO4(s) + NaCl(aq)
While writing the chemical reaction for the oxidation of calcium in oxygen, a student wrote the following balanced equation:
Ca + O→ CaO
Is it correct? If not, explain and write the correct balanced equation.
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