# Balancing the chemical equation using Oxidation Number Method [closed]

Permanganate ion reacts with bromide ion in basic medium to give manganese dioxide and bromate ion. Write the balanced ionic equation for the reaction.

Please balance the equation using the oxidation number method. The skeletal ionic equation is:

$$\ce{MnO4-(aq) + Br-(aq) -> MnO2(s) + BrO3-(aq)}$$

This question is asked in Problem 8.9, NCERT Textbook Class XI, Pg. no. 267. My answer to this question is different from the answer given in the book. I'd love to know the correct answer to this question.

• You may want tp write down the expected answer, your answer and your reasoning for it. It may prevent closing your question as "not elaborated homowork class question". – Poutnik Aug 19 '19 at 10:20

\begin{align} \ce{\overset{+7}{Mn}O4- + 2 H2O + 3 e- &→ \overset{+4}{Mn}O2 + 4 OH-} &\quad |\cdot 2 \tag{red}\\ \ce{\overset{-1}{Br}^- + 6 OH- &→ \overset{+5}{Br}O3- + 3 H2O + 6 e-} &\quad \tag{ox}\\ \hline \ce{2 MnO4- + Br- + H2O &→ 2 MnO2 + BrO3- + 2 OH-} \tag{redox} \end{align}
As a sanity check, you can see that there are no protons $$\ce{H+}$$ participating in either of the reactions, and the resulting medium is indeed basic (slight excess of $$\ce{OH-}$$), which is in a good agreement with the conditions mentioned in the problem.