Question

In the conversion of $B{r}_2$ to $Br{O}_3^{-},$ 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 $\stackrel{0}{B{r}_2}\to Br{O}_3^{-}$ $Br{O}_3^{-}$ $x+(-2\times 3)=-1$ $x+(-6)=-1$ $x=+6-1$ $=+5$ So, oxidation number changes from 0 to + 5.