Chapter 20.7, Problem 1.1ACP

(a)

Interpretation Introduction

Interpretation:

The given reaction is whether a disproportionation should be explained

Concept introduction:

• In a disproportionation reaction an element’s oxidation number will vary in accordance with the chemical conditions.
• In cathode, reduction reaction will take place and in an anode oxidation reaction will happen.

(b)

Interpretation Introduction

Interpretation:

The value of equilibrium constant for the reaction should be determined

Concept introduction:

• If the oxidation number of an element increases then the element is said to be oxidized and the oxidation number value of decreases for an element which is reduced.

  $E_{cell}^0=E_{cathode}^0-E_{anode}^0$

• In cathode, reduction reaction will take place and in an anode oxidation reaction will happen.
• The equation to determine the equilibrium constant $K$ by using the value of $E^0$ is,

  $\ln K=\frac{n{E}^0}{0.0257}$     n is the number of electrons involved in the reaction

(c)

Interpretation Introduction

Interpretation:

It should be checked whether the given reaction is a disproportionation reaction (a), calculate the value of ${\text{E}}^{\text{0}}\text{and}\text{equilibrium}\text{constant}\text{K}$ for the reaction (b) and it should be explained that change in $pH$ will affect the value of $E$ or not.

Concept introduction:

• In cathode, reduction reaction will take place and in an anode oxidation reaction will happen.
• pH: The concentration of hydrogen ion is measured using $\text{pH}$ scale.  The acidity of aqueous solution is expressed by $\text{pH}$ scale.
• Changing value of $pH$ will greatly affect the equilibrium of a reaction.