Question

Q.4 State whether the underlined substance in each case has undergone oxidation or reduction giving reasons for your answer:- (i) PbO2+4HCl→PbCl2 +2H2 O+ Cl2 (ii) SO2 +Cl 2 + H2 O →2HCl +H2 SO4 + H2O (iii) S +6HNO3→H2 SO4 + 6NO2 (iv) Fe2O3+3CO →2Fe + 3CO2

Answer 1

Answer:

1. PbO2 undergoes reduction, HCl undergoes oxidation

2. SO2 undergoes oxidation, Cl undergoes reduction, H2O does not undergo reaction.

3. S undergoes oxidation, HNO3 undergoes reduction

4. Fe2O3 undergoes reduction, CO undergoes oxidation.

Answer 2

Answer:

ans (i) - Lead dioxide has undergone reduction due to the step down in the

valency of lead from 2 to 3.

ans (ii) - Chlorine has reduced itself to form HCl by the addition of hydrogen.

ans(iii) - Sulphur has accepted oxygen and oxidised itself to sulphuric

acid

ans(iv) -Carbon monoxide has formed carbon dioxide by accepting

oxygen and is oxidized.

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