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Consider the following pairs of reactions and properties: Reactions Properties I. Fe(s) + 2 HCl(aq) FeCl ₂ (aq) + H ₂ (g) Fe is reductant II. Zn(s) + CuSO ₄ (aq) ZnSO ₄ (aq) + Cu(s) Cu is being reduced III. Br ₂ (l) + 2 I ^- (aq) 2 Br ^- (aq) + I ₂ (s) Br ₂ is reductant IV. CH ₄ (g) + 2 O ₂ (g) CO ₂ (g) + 2 H ₂ O(l) C atom in CH ₄ is oxidized Which of the above pairs are correct?

Options

  1. AI and II only
  2. BII, III and IV
  3. CI, II and IV
  4. DI, III and IV

Correct answer

C. I, II and IV

Step-by-step solution

Reaction I: Fe changes its oxidation state from 0 to +2 . It undergoes oxidation and acts as a reductant. Pair I is correct. Reaction II: Cu in CuSO ₄ changes its oxidation state from +2 to 0 . It undergoes reduction. Pair II is correct. Reaction III: Br ₂ changes its oxidation state from 0 to -1 . It undergoes reduction and acts as an oxidant, not a reductant. Pair III is incorrect. Reaction IV: C in CH ₄ changes its oxidation state from -4 to +4 . It undergoes oxidation. Pair IV is correct. Therefore, pairs I, II

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