Chapter 17.3, Problem 17.7P

(a)

Interpretation Introduction

Interpretation:

Balanced equation for reaction below by change-in-oxidation-number method in basic solution has to be determined.

  $\text{Zn}\to \text{Zn}{\left(\text{OH}\right)}_4^{2-}+{\text{H}}_{\text{2}}$

Concept Introduction:

Change in oxidation number method to balance redox reactions.

1. Oxidation number of each element has to be assigned and change in oxidation number has to be identified. Then add electrons to balance charge.

2. Two half-reactions with only elements that have changed oxidation numbers have to be formed.

3. Both reactions multiplied by smallest whole number that can make electrons lost equal to electron gained.

4. Coefficient should transferred to original equation.

5. Remaining oxygen atoms are balanced through water molecules.

6. For acidic medium, charge is balanced by addition of ${\text{H}}^{+}$ ion.

(b)

Interpretation Introduction

Interpretation:

Balanced equation for reaction below by change-in-oxidation-number method in acidic solution has to be determined.

  ${\text{H}}_2{\text{O}}_2+{\text{Sn}}^{2+}\to {\text{Sn}}^{4+}$

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

Balanced equation for reaction below by change-in-oxidation-number method in basic solution has to be determined.

  $\text{Cu}+{\text{Cu}}^{2+}\to {\text{Cu}}_2\text{O}$

Concept Introduction:

Refer to part (a).