# sulfur dioxide gas bubbles through acidified potassium

Sulfur dioxide gas (SO2) is bubbled through a solution of acidified potassium permanganate (KMnO4). An oxidation-reduction reaction occurs. The unbalanced equation for this reaction is:

MnO4– + SO2–> Mn2+ + SO42–

A student wrote the two following half-equations:

Equation One MnO4– + 8H+ + 5e– –> Mn2+ + 4H2O

Equation Two SO2 + 4H+ + 2e– –> SO42– + 2H2O

It is not possible to combine these two half-equations as the student had written Equation Two incorrectly.

1. Describe the mistake that was made in Equation Two.

2. Write Equation Two correctly.

(Discuss, in terms of oxidation-reduction principles, electron transfer and charge, why Equation One and the original Equation Two cannot be combined into an overall balanced equation.)

3. Hydrogen peroxide is added to a solution of potassium bromide.You may use the resource tables given at the end of this assignment to help you answer the following questions. Identify which substance is being reduced. Use oxidation numbers and the transfer of electrons to justify your choice.

4.Describe what you would expect to observe for this reaction. Link all observations

to the species concerned. (Tip: remember to describe both reactants and products.)

5.Write the balanced oxidation half reaction.

6. Write the balanced reduction half reaction

7. Write the full balanced equation.