Chapter 20.12, Problem 20.20P

Interpretation Introduction

Interpretation:

For the given hydrogenation reaction of ${\text{N}}_{\text{2}}$ the value of ${\text{ΔG}}^{\text{o}}$ for each step has to be calculated and also the favorable step under standard state conditions has to be identified.

Concept Introduction:

Standard Gibb’s free energy change of reaction:

Gibb’s free energy change of reaction at standard state is given by

$\begin{array}{l}{\text{ΔG}}^{\text{o}}\text{=}\left({\displaystyle \sum {\text{n}}_{\text{p}}{\text{ΔG}}_{\text{f}}^{\text{o}}\text{products}}\right)\text{-}\left({\displaystyle \sum {\text{n}}_{\text{r}}{\text{ΔG}}_{\text{f}}^{\text{o}}\text{reactants}}\right)\\ \text{where,}\\ {\text{ΔG}}^{\text{o}}\text{-}\text{standard}\text{free}\text{energy}\text{change}\text{of}\text{reaction}\\ {\text{ΔG}}_{\text{f}}^{\text{o}}\text{-}\text{standard}\text{free}\text{energy}\text{change}\text{of}\text{formation}\\ {\text{n}}_{\text{p}}\text{and}{\text{n}}_{\text{r}}\text{-}\text{number}\text{of}\text{moles}\text{of}\text{product}\text{and}\text{reactant}\end{array}$

If the value of ${\text{ΔG}}^{\text{o}}$ is more negative for a reaction then the given reaction is more favorable.