Chapter 19.1, Problem 1PE

Interpretation Introduction

Interpretation:

The given reaction in acidic medium by the ion- electron method has to be balanced.

Concept Introduction:

Ion-electron method: a way to balance a redox equation.

In the ion-electron method (also called the half-reaction method), the redox equation is separated into two half-reactions. One half-reaction for oxidation and another for reduction; further the reactions are balanced by following procedure.

Procedure for balancing redox equations:

Step 1: Write the unbalanced equation for the reaction in ionic form.

Step 2: Separate the equation into two half-reactions.

Step 3: Balance each half-reactions in number and type of atoms and charges. For reactions in an acidic medium, add ${\text{H}}_{\text{2}}\text{O}$ to balance the $O$ atoms and $H^{+}$ to balance the $H$ atoms.

Step 4: Add the two half-reactions together and balance the final equation. The equation must be atomically and electrically balanced. In case of different number of electrons, need to multiply one or both half-reactions to equalize the number of electrons.

Step 5: Finally, the number and type of atoms; charges on both sides of the equation must be same and balanced.