Which of these are oxidation-reduction reactions?
I. PCl₃ + 3H₂O → 3HCl + H₃PO₃
II. Fe₂O₃ + 3CO → 2Fe + 3CO₂
III. CaCO₃ + HClO₃ → Ca(ClO₃) ₂ + CO₂ + H₂O

Question

Which of these are oxidation-reduction reactions? I. PCl₃ + 3H₂O → 3HCl + H₃PO₃ II. Fe₂O₃ + 3CO → 2Fe + 3CO₂ III. CaCO₃ + HClO₃ → Ca(ClO₃)₂ + CO₂ + H₂O

Quizplus · Accepted Answer

In oxidation-reduction reactions, one substance is oxidized (loses electrons) while another substance is reduced (gains electrons). In reaction II, Fe2O3 is reduced (Fe3+ is reduced to Fe) while CO is oxidized (C is oxidized from 0 to +2).

Which of These Are Oxidation-Reduction Reactions