Question

Balancing of redox reaction

Answer 1

Explanation:

In the ion-electron method (also called the half-reaction method), the redox equation is separated into two half-equations - one for oxidation and one for reduction. Each of these half-reactions is balanced separately and then combined to give the balanced redox equation.

Answer 2

Answer:

Two methods are used to balance chemical equation for redox processes: Oxidation number method and Half reaction method or Ion electron method.

(1) Oxidation number method:

Step 1 : Balance the given equation for all atoms except H and O. Identify the atoms undergoing change in oxidation number.

Step 2 : Show an increase in oxidation number for oxidised species and a decrease in oxidation number for reduced species. Balance total increase and decrease in oxidation numbers.

Step 3 : Balance O atoms by adding H_2O to the side deficient of O atoms and balance H atoms by adding H^+ ions to the side deficient of H atoms and they are finally removed by forming H_2O.

Step 4: In basic medium OH^-ions are added which are removed as H_2O.

Step 5: Check the equation with respect to number of atoms of each element on both the sides.

(2) Half reaction methods :

Step 1: Assign oxidation numbers to all atoms in the given reaction.

Step 2 : Divide the equation into two half equations, one for oxidation and the other for reduction.

Step 3: Find the loss of electrons and gain of electrons by atoms in the reaction.

Step 4: Balance the loss and gain of electrons.

Step 5: Add both the reactions.

Step 6: For acidic medium H^+ ions are added while for basic medium OH^- are added.