Chapter 17, Problem 16PE

(a)

Interpretation Introduction

Interpretation:

Below reaction by ion electron method in acidic medium has to be balanced.

  ${\text{ClO}}_3+{\text{I}}^{-}\to {\text{I}}_2+{\text{Cl}}^{-}$

Concept Introduction:

Rules to balance redox reactions by ion-electron method are as follows:

1. Two half-reactions with elements that got oxidized and reduced should be written.

2. Elements other than oxygen and hydrogen should be balanced.

3. Conditions to balance $\text{O}$ and $\text{H}$ are as follows:

In acidic solution, ${\text{H}}^{+}$ and ${\text{H}}_2\text{O}$ should be used to balance $\text{O}$ and $\text{H}$.

In basic solution, equal ${\text{OH}}^{-}$ ions to ${\text{H}}^{+}$ ions should be added on both sides of balanced reaction in acidic medium.

4. For acidic medium, charge is balanced by addition of ${\text{H}}^{+}$ ion. Then combine ${\text{H}}^{+}$ and ${\text{OH}}^{-}$ to form ${\text{H}}_2\text{O}$ and cancel common ${\text{H}}_2\text{O}$ in reaction.

5. Electrons should be added to balance electric charge.

6. Finally, two half-reactions should be added and any common substance including electrons must be cancelled.

(b)

Interpretation Introduction

Interpretation:

Below reaction by ion electron method in acidic medium has to be balanced.

  ${\text{Cr}}_2{\text{O}}_7^{2-}+{\text{Fe}}^{2+}\to {\text{Cr}}^{3+}+{\text{Fe}}^{3+}$

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

Below reaction by ion electron method in acidic medium has to be balanced.

  ${\text{MnO}}_4{}^{-}+{\text{SO}}_2\to {\text{Mn}}^{2+}+{\text{SO}}_4{}^{2-}$

Concept Introduction:

Refer to part (a).

(d)

Interpretation Introduction

Interpretation:

Below reaction by ion electron method in acidic medium has to be balanced.

  ${\text{HAsO}}_3+{\text{MnO}}_4{}^{-}\to {\text{H}}_3{\text{AsO}}_4+{\text{Mn}}^{2+}$

Concept Introduction:

Refer to part (a).

(e)

Interpretation Introduction

Interpretation:

Below reaction by ion electron method in acidic medium has to be balanced.

  ${\text{HAsO}}_3+{\text{Cr}}_2{\text{O}}_7^{2-}\to {\text{H}}_3{\text{AsO}}_4+{\text{Cr}}^{3+}$

Concept Introduction:

Refer to part (a).