Question

Consider the following reaction occuring in basic medium $2 MnO _{4}^{-}( aq )+ Br ^{-}( aq ) \longrightarrow 2 MnO _{2}( s )+ BrO _{3}^{-}( aq )$ How the above reaction can be balanced further?

• A. By adding $2 OH ^{-}$ions on right side
• B. By adding one $H _{2} O$ molecule to left side
• C. By adding $2 H ^{+}$ions on right side
• D. Both (a) and (b)

Answer 1

Answer: (D)

Since reaction is occuring in basic medium, therefore, $2 OH ^{-}$ are added on right side.
$2 MnO _{4}^{-}( aq )+ Br ^{-}( aq ) \longrightarrow 2 MnO _{2}( s )+ BrO _{3}^{-}( aq )+2 OH ^{-}( aq ) $
Now, hydrogen atoms can be balanced by adding one $H _{2} O$ molecule to the left side
$2 MnO _{4}^{-}( aq )+ Br ^{-}( aq )+ H _{2} O ( l ) \longrightarrow $
$2 MnO _{2}( s )+ BrO _{3}^{-}( aq )+2 OH ^{-}( aq )$