For the reaction between $\mathrm{MnO}_{4}^{-}$and $\mathrm{C}_{2} \mathrm{O}_{4}^{2-}$ in basic med

Question

For the reaction between $\mathrm{MnO}_{4}^{-}$and $\mathrm{C}_{2} \mathrm{O}_{4}^{2-}$ in basic medium,\ $\mathrm{MnO}_{4}^{-}+\mathrm{C}_{2} \mathrm{O}_{4}^{2-}+\mathrm{OH}^{-} ightarrow \mathrm{MnO}_{2}+\mathrm{CO}_{3}^{2-}$, the number of $\mathrm{OH}^{-}$ions in the balanced equation is\

Professor PC Thomas Classes · Answer

Cross multiply\ $2 \mathrm{MnO}_{4}^{-}+3 \mathrm{C}_{2} \mathrm{O}_{4}^{2-} ightarrow 2 \mathrm{MnO}_{2}+6 \mathrm{CO}_{3}^{2-}$\ Balance w.r.t oxygen by adding required no of $\mathrm{H}_{2} \mathrm{O}$.\ $2 \mathrm{MnO}_{4}^{-}+3 \mathrm{C}_{2} \mathrm{O}_{4}^{2+}+2 \mathrm{H}_{2} \mathrm{O} ightarrow 2 \mathrm{MnO}_{2}+6 \mathrm{CO}_{3}^{2-}$\ Balance w.r.t hydrogen by adding required no. of $\mathrm{H}_{2} \mathrm{O}$ molecule on the side where there is shortage of H atoms and equal number of $\mathrm{OH}^{-}$on the other side\ $2 \mathrm{MnO}_{4}^{-}+3 \mathrm{C}_{2} \mathrm{O}_{4}^{2-}+2 \mathrm{H}_{2} \mathrm{O} ightarrow 2 \mathrm{MnO}_{2}+6 \mathrm{CO}_{3}^{2-}$\ $+4 \mathrm{OH}^{-} \quad+4 \mathrm{H}_{2} \mathrm{O}$\ $2 \mathrm{MnO}_{4}^{-}+3 \mathrm{C}_{2} \mathrm{O}_{4}^{2-}+4 \mathrm{OH}^{-} ightarrow 2 \mathrm{MnO}_{2}+6 \mathrm{CO}_{3}^{2-}+2 \mathrm{H}_{2} \mathrm{O}$\