Question

Explain the equation:
Permanganate ion reacts with bromide ion in basic medium to give MnO2 and Br-

Answer 1

The equation of permanganate ion and bromide ion to give MnO2 and Br– can be described by four steps. These are

•Step 1:Thee skeletal ionic equation is

MnO4- + Br- ———> MnO2+BrO3-

•Step 2: Assign oxidation numbers for Mn and Br

MnO4- + Br- ———> MnO2+BrO3-

this indicates that permanganate ion is the oxidant and bromide ion is the reductant.

•Step 3: Calculate the increase and decrease of oxidation number, and make the increase equal to the decrease.

MnO4- + Br- ———> 2MnO2+BrO3-

•Step 4: As the reaction occurs in the basic medium and the ionic charges are not equal on both sides, add 2 OH ions on the right to make ionic charges equal.

MnO4- + Br- ———> MnO2+BrO3-

•Step 5 Finally, count the hydrogen atoms and add appropriate number of water molecules .

2MnO4-+Br-+H2O——> 2MnO2+BrO3-+ 2OH-