To determine which chemical equation represents a redox reaction, we should first understand what a redox (reduction-oxidation) reaction is. In a redox reaction, one element undergoes oxidation (loss of electrons) and another element undergoes reduction (gain of electrons).
Let's analyze the given options:
Option A:
[tex]\[ Mg(ClO_3)_2 + 2 HCl \rightarrow MgCl_2 + 2 HClO_3 \][/tex]
This reaction does not involve any changes in the oxidation states of the elements involved. Therefore, it is not a redox reaction.
Option B:
[tex]\[ CO + H_2O \rightarrow H_2 + CO_2 \][/tex]
In this reaction:
- Carbon in CO goes from an oxidation state of +2 to +4 in CO₂ (oxidation).
- Hydrogen in H₂O goes from an oxidation state of +1 to 0 in H₂ (reduction).
This reaction involves both reduction and oxidation processes. Therefore, this equation represents a redox reaction.
Option C:
[tex]\[ 2 NH_4NO_3 + CuCl_2 \rightarrow 2 NH_4Cl + Cu(NO_3)_2 \][/tex]
This reaction does not involve any changes in the oxidation states of the elements. Therefore, it is not a redox reaction.
Option D:
[tex]\[ Na_2SO_3 + FeBr_2 \rightarrow 2 NaBr + FeSO_3 \][/tex]
This reaction does not show any changes in the oxidation states of the elements involved. Therefore, it is not a redox reaction.
Based on the analysis of the oxidation states and the concept of redox reactions, the correct answer is:
[tex]\[ \boxed{B} \][/tex]
