In the following reaction:3Br2 +6CO32- + 3H2O → 5Br-1 + BrO3-1 + 6HCO3-1
Correct answer: B. Bromine is both reduced and oxidized.
- A. Bromine is reduced and water is oxidized.
- B. Bromine is both reduced and oxidized.
- C. Bromine is oxidized and carbonate is reduced.
- D. Bromine is neither reduced nor oxidized.
Explanation
The correct answer is that bromine is both reduced and oxidized. This reaction is an example of a disproportionation reaction. In Br2, bromine has an oxidation state of 0. It is reduced to form bromide ions (Br-1), where the oxidation state is -1, and it is oxidized to form bromate ions (BrO3-1), where the oxidation state is +5. Therefore, bromine undergoes both a decrease and an increase in oxidation state. Other elements, such as hydrogen, carbon, and oxygen, do not experience any change in their oxidation states during this reaction.
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