AIIMS 2010 Chemistry Disproportionation Reactions MCQ Question

In the reaction of bromine with cold dilute aqueous NaOH, bromine undergoes a series of oxidation state changes. The oxidation states of bromine that can be observed include -1 (in bromide ions), 0 (in elemental bromine), +1 (in hypobromite), +3 (in bromite), +5 (in bromate), and +7 (in perbromate). Thus, bromine can exist in multiple oxidation states, specifically -1, 0, +1, +3, +5, and +7. Therefore, statement A is true. The greatest difference between the various oxidation states of bromine is indeed 7 (from -1 to +7), making statement B false. On acidification of the final mixture, bromine is released as a result of the reaction, confirming statement C as true. Disproportionation occurs as bromine is both oxidized and reduced during the reaction, validating statement D as true. Hence, the correct answer is B, as it incorrectly states the maximum difference in oxidation states as 5 instead of 7.