Chapter 19, Problem 19.53SP

Interpretation Introduction

(a)

Interpretation:

The balanced net ionic equation for the reaction ${\text{S}}_2{\text{O}}_3^{2-}{\text{(aq) + I}}_2\text{(aq) }\to {\text{ S}}_4{\text{O}}_6{}^{2-}{\text{(aq) + I}}^{-}\text{(aq)}$ in basic solution should be written.

Concept introduction:

The half reaction method can be used to balance redox equation using following steps.

• Atoms which are oxidized and which are reduced should be determined.
• The two unbalanced half-cell reactions are written.
• Then the elements in the reaction except oxygen and hydrogen should be balanced.
• Oxygen atoms are balanced by adding water molecules to opposite side of the equation.
• Hydrogen atoms are balanced by adding ${\text{H}}^{+}$ ions to the opposite side of the equation. In basic medium ${\text{OH}}^{-}$ ions are added to neutralize ${\text{H}}^{+}$ ions in the final step.
• Charges are made equal by adding electrons to more positive side.
• The two half reactions are multiplied by a suitable factor to equal the electron count in both half-equations.
• Two balanced half-equations are added together and electrons and other common species are cancelled.

Interpretation Introduction

(b)

Interpretation:

The balanced net ionic equation for the reaction ${\text{ClO}}^{-}{\text{(aq) + MnO}}_2\text{(s) }\to {\text{ Cl}}^{-}{\text{(aq) + MnO}}_4^{-}\text{(aq)}$ in basic solution should be written.

Concept introduction:

The half reaction method can be used to balance redox equation using following steps.

• Atoms which are oxidized and which are reduced should be determined.
• The two unbalanced half-cell reactions are written.
• Then the elements in the reaction except oxygen and hydrogen should be balanced.
• Oxygen atoms are balanced by adding water molecules to opposite side of the equation.
• Hydrogen atoms are balanced by adding ${\text{H}}^{+}$ ions to the opposite side of the equation. In basic medium ${\text{OH}}^{-}$ ions are added to neutralize ${\text{H}}^{+}$ ions in the final step.
• Charges are made equal by adding electrons to more positive side.
• The two half reactions are multiplied by a suitable factor to equal the electron count in both half-equations.
• Two balanced half-equations are added together and electrons and other common species are cancelled.

Interpretation Introduction

(c)

Interpretation:

The balanced net ionic equation for the reaction ${\text{Zn(s) + NO}}_3{}^{-}\text{(aq) }\to {\text{ NH}}_3{\text{(aq) + Zn(OH)}}_4^{2-}\text{(aq)}$ in basic solution should be written.

Concept introduction:

The half reaction method can be used to balance redox equation using following steps.

• Atoms which are oxidized and which are reduced should be determined.
• The two unbalanced half-cell reactions are written.
• Then the elements in the reaction except oxygen and hydrogen should be balanced.
• Oxygen atoms are balanced by adding water molecules to opposite side of the equation.
• Hydrogen atoms are balanced by adding ${\text{H}}^{+}$ ions to the opposite side of the equation. In basic medium ${\text{OH}}^{-}$ ions are added to neutralize ${\text{H}}^{+}$ ions in the final step.
• Charges are made equal by adding electrons to more positive side.
• The two half reactions are multiplied by a suitable factor to equal the electron count in both half-equations.
• Two balanced half-equations are added together and electrons and other common species are cancelled.