Chapter 18, Problem 18.141MP

Interpretation Introduction

(a)

Interpretation:

The chemical equation for the reaction needs to be balanced in basic solution.

Concept introduction:

An equation for a chemical reaction is said to be balanced, if there are equal number of atoms present on both sides of the reaction arrow.

For any redox reaction, the first step is to determine the two half reactions.

To balance the chemical equation in acid medium, initially atoms other than oxygen and hydrogen are balanced. After that oxygen atoms are balanced by adding ${\text{H}}_{\text{2}}\text{O}$ on the side with lesser number of O atoms. The hydrogen atoms are balanced by adding ${\text{H}}^{+}$ ions.

For basic solution, add ${\text{OH}}^{-}$ to both side of the reaction equal to the ${\text{H}}^{+}$ ions in order to neutralize it.

Interpretation Introduction

(b)

Interpretation:

The value of $\Delta G_{}^o$ for the reaction needs to be calculated.

Concept introduction:

For a general reaction as follows:

$A+B\to C\text{}+D$

The change in Gibbs free energy of reaction can be calculated as follows:

$\Delta {\text{G}}^o{}_{rxn}\text{=}{\displaystyle \sum \Delta {\text{G}}_f^o\left(\text{product}\right)-}{\displaystyle \sum \Delta {\text{G}}_f^o\left(\text{reactant }\right)}$

Interpretation Introduction

(c)

Interpretation:

Whether the given reaction is spontaneous or non-spontaneous needs to be determined.

Concept introduction:

The given reaction is said to be spontaneous if the value of $\Delta G_{rxn}^o$ is negative and it is non- spontaneous if the value of $\Delta G_{rxn}^o$ is positive.

Interpretation Introduction

(d)

Interpretation:

The value of pH required for the reaction to exist in equilibrium needs to be determined.

Concept introduction:

The pH of the solution can be calculated from pOH as follows:

$pH=14-\text{pOH}$

Also,

$\text{pOH=}-\text{log}\left[{\text{OH}}^{-}\right]$

Here, $\left[{\text{OH}}^{-}\right]$ is concentration of hydroxide ion.