Chapter 21, Problem 61PS

Interpretation Introduction

Interpretation: To predict the stability of oxides of nitrogen with respect to decomposition to ${\text{N}}_{\text{2}}$ and ${\text{O}}_{\text{2}}$.

Concept introduction: The general formula of oxides of nitrogen is ${\text{N}}_{\text{x}}{\text{O}}_{\text{y}}$. The decomposition reaction is:

    ${\text{N}}_{\text{x}}{\text{O}}_{\text{y}}\to \frac{\text{x}}{\text{2}}{\text{N}}_{\text{2}}\text{+}\frac{\text{y}}{\text{2}}{\text{O}}_{\text{2}}$

Some of the common oxides of nitrogen are $\text{NO}$, ${\text{NO}}_{\text{2}}$, ${\text{N}}_{\text{2}}\text{O}$ and ${\text{N}}_{\text{2}}{\text{O}}_{\text{4}}$.

The change in the free energy value is given by the equation,

$\begin{array}{l}\Delta G=\Delta H-T\Delta S\\ \Delta GFreeenergychange\\ \Delta HEnthalpychange\\ TTemperature\\ \Delta SEntropychange\end{array}$

For a spontanoes process the $\Delta G$ value will be negative.