Question

In the conversion of $ B{{r}_{2}} $ to $ BrO_{3}^{-}, $ the oxidation number of Br changes from

• A. zero to $ +5 $
• B. $ +1 $ to $ +5 $
• C. zero to $ -3 $
• D. $ +2 $ to $ +5 $

Answer 1

Answer: (A)

Bromine has zero oxidation state because it is in free state $ \overset{0}{\mathop{B}}\,{{r}_{2}}\xrightarrow[{}]{{}}BrO_{3}^{-} $ $ \overset{x}{\mathop{B}}\,O_{3}^{-\underline{2}} $ $ x+(-2\times 3)=-1 $ $ x+(-6)=-1 $ $ x=+6-1 $ $ =+5 $ So, oxidation number changes from 0 to $ +5 $ .