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 -1-5

Answer 1

Answer: (A)

Bromine has zero oxidation state because it is in free state
${\stackrel{0}{\mathrm{Br}}}_2⟶Br{O}_3^{-}$
$x+(-2\times 3)=-1$
$x+(-6)=-1$
$x=+6-1$
$=+5$
So, oxidation number changes from $0$ to $+5$.