Question

In the conversion of $Br _{2}$ 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 -1-5

Answer 1

Answer: (A)

Bromine has zero oxidation state because it is in free state
$\overset{0}{ Br }_{2} \longrightarrow BrO _{3}^{-}$
$x+(-2 \times 3) =-1$
$x+(-6) =-1$
$x =+6-1$
$=+5$
So, oxidation number changes from $0$ to $+5$.