Chapter 18, Problem 18.55QP

(a)

Interpretation Introduction

Interpretation:

The equilibrium $(K)$ value has to be predicted given acid-base reaction at $25°C$    

Concept Introduction:

Bronsted's definition is based on the chemical reaction that occurs when both acids and bases are added with each other. In Bronsted's theory acid donates proton, while base accepts proton from acid resulting in the formation of water.

According to Lewis theory, acid and base can be defined as follows.

Lewis Acid:

Lewis acid is a substance that can accept a pair of electrons

Example: $\text{BF}{\text{3}}_{}$

Lewis Base:

Lewis base is a substance that can donate a pair of electrons.

Example: ${\text{NH}}_{\text{3}}$

(b)

Interpretation Introduction

Interpretation:

Given acid-base reaction standard free energy $(\Delta G°)$ value has to be calculated and identified

Concept Introduction:

Thermodynamics is the branch of science that relates heat and energy in a system.  The four laws of thermodynamics explain the fundamental quantities such as temperature, energy and randomness in a system.  Entropy is the measure of randomness in a system.  For a spontaneous process there is always a positive change in entropy. Free energy (Gibbs free energy) is the term that is used to explain the total energy content in a thermodynamic system that can be converted into work.  The free energy is represented by the letter G.  All spontaneous process is associated with the decrease of free energy in the system.  The equation given below helps us to calculate the change in free energy in a system.

$\text{ΔG}°\text{ = }\Delta {\rm H}°\text{- T}\Delta \text{S}°$

Where,

  $\text{ΔG}°$ is the change in standard free energy of the system

  $\Delta {\rm H}°$ is the change in standard enthalpy of the system

  $\text{T}$ is the absolute value of the temperature

  $\Delta \text{S}°$ is the change in standard entropy in the system

(c)

Interpretation Introduction

Interpretation:

Given acid-base reaction $(\Delta {\rm H}°)$ signs should be identified

Concept Introduction:

Thermodynamics is the branch of science that relates heat and energy in a system.  The four laws of thermodynamics explain the fundamental quantities such as temperature, energy and randomness in a system.  Entropy is the measure of randomness in a system.  For a spontaneous process there is always a positive change in entropy. Free energy (Gibbs free energy) is the term that is used to explain the total energy content in a thermodynamic system that can be converted into work.  The free energy is represented by the letter G.  All spontaneous process is associated with the decrease of free energy in the system.  The equation given below helps us to calculate the change in free energy in a system.

$\text{ΔG}°\text{ = }\Delta {\rm H}°\text{- T}\Delta \text{S}°$

Where,

  $\text{ΔG}°$ is the change in standard free energy of the system

  $\Delta {\rm H}°$ is the change in standard enthalpy of the system

  $\text{T}$ is the absolute value of the temperature

  $\Delta \text{S}°$ is the change in standard entropy in the system