Chapter 20, Problem 30QAP

Interpretation Introduction

(a)

Interpretation:

The equilibrium constant (K) for disproportionation of Au+ ion should be calculated using the given table.

Concept introduction:

Disproportionation reaction is a special type of redox reaction in which the reacting species has a special ability to undergo oxidation and reduction simultaneously. It forms two types of compound or species, one with higher oxidation state and another with lower oxidation state.

The relation between Gibb’s free energy change and K can be used to find the equilibrium constant (K) value as:

$\begin{array}{l}\text{ΔG=-2}\text{.303RT logK}\\ \text{ΔG=-}nF{E}^0\\ \text{Equating both the formula we get:}\\ \text{-}nF{E}^0=\text{-2}\text{.303RT logK}\\ Or,\\ nF{E}^0=2.\text{303RT logK}\end{array}$

Where n is number of electrons involved, F is Faraday’s constant (96485 J/mol), R is Universal gas constant and T is temperature.

Interpretation Introduction

(b)

Interpretation:

The concentration of Au+ in equilibrium with 0.10 M Au+3 should be calculated.

Concept introduction:

The equilibrium constant is expressed as: the ratio of concentration of product raised to the power of their stoichiometric co-efficient to the concentration of reactant raised to the power of their stoichiometric co-efficient at equilibrium conditions so as:

$\text{K=}\frac{\text{[Product]}}{\text{[Reactant]}}$