Ex-1 Which of the statements about the reaction below are incorrect? 2PbO(s) + C(s) → 2Pb(s) + CO2 (g)

CBSE Class 10 Chemistry Chapter 1 - Chemical Reactions and Equations Exercise 1

Which of the statements about the reaction below are incorrect? 

2PbO(s) + C(s) → 2Pb(s) + CO2 (g) 

(a) Lead is getting reduced. 

(b) Carbon dioxide is getting oxidised. 

(c) Carbon is getting oxidised. 

(d) Lead oxide is getting reduced.


Looking at the reaction: 2PbO(s) + C(s) → 2Pb(s) + CO2(g)

Initial oxidation states:

  • In PbO: Pb = +2, O = -2
  • In C: C = 0

Final oxidation states:

  • In Pb: Pb = 0
  • In CO2: C = +4, O = -2

Changes:

  • Lead: +2 → 0 (decrease in oxidation state = reduction)
  • Carbon: 0 → +4 (increase in oxidation state = oxidation)

Now examining each statement:

(a) Lead is getting reduced - CORRECT Lead's oxidation state decreases from +2 to 0.

(b) Carbon dioxide is getting oxidised - INCORRECT CO2 is a product, not a reactant. It's not "getting" oxidized - it's the result of carbon's oxidation. The carbon within CO2 is already in the +4 oxidation state.

(c) Carbon is getting oxidised - CORRECT Carbon's oxidation state increases from 0 to +4.

(d) Lead oxide is getting reduced - CORRECT PbO contains lead in the +2 state, which gets reduced to 0. When we say "lead oxide is getting reduced," we're referring to the lead component being reduced.

Answer: Statement (b) is incorrect.


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