Question

Bromine is added to cold dilute aqueous solution of NaOH. Then the mixture is boiled. Which of the following statements is not true? 

(a) During the reaction bromine is present in four different oxidation states. 

(b) The greatest difference between the various oxidation states of bromine is 5. 

(c) On acidification of the final mixture bromine is formed. 

(d) Disproportionation of bromine occurs during the reaction.

Answer 1

The correct option is (b) The greatest difference between the various oxidation states of bromine is 5. 

Explanation:

Thus, during the reaction, bromine is present in four different oxidation states i.e., zero in Br₂, + 1 in NaBrO, -1 in NaBr and +5 in NaBrO₃. The greatest difference between various oxidation states of bromine is 6 and not 5. On acidification of the final mixture, Br₂ is formed and disproportionation of Br₂ occurs during the reaction giving BrO^-, Br^- and BrO₃^- ions.