Thermodynamic stability of benzene derivatives Q1. How can we comment on the thermodynamic stability of the following benzene derivatives? 



Q2. What does thermodynamic stability mean, in general? What does it mean to compare the thermodynamic stability of more than compound? 

Q3. How do we compare the thermodynamic stability of benzene derivatives? Is there a specific rule, or way to go about it? Would MOT (frost circles, to be specific) help?

I looked at the extent of resonance, and other such stabilizing phenomena/interactions. However, that only tells the extent of stabilisation of the compound due to those phenomena, not as a whole. 

Edit: I wish to predict the order of stability using knowledge of chemistry, and not check enthalpy of formation data and then establish the order.
Wikipedia defines thermal stability as . 


  Thermodynamic stability occurs when a system is in its lowest energy state, or chemical equilibrium with its environment. This may be a dynamic equilibrium, where individual atoms or molecules change form, but their overall number in a particular form is conserved.  


For the particular problem in hand the lowest energy state definition is more relevant for us .      

Enthalpy of formation can be used for judging the energy states.  

A  negative enthalpy change implies that the product has released heat thus lowering the amount of energy present in the product 

This implies. 


  More negative the enthalpy of formation, more stable the compound.  




Enthalpies of formation    


Phenol
$\ce{ -&gt; -165.0 kJ/mol}$.      
Hydroquinone
$\ce{-&gt; -371.1 ± 1.3 kJ/mol}$     
P-Nitrophenol
$\ce{-&gt; -207.1 ± 1.1 kJ/mol}$   


 
All data has been taken from http://webbook.nist.gov , for solid state. 
 



The order can be calculated now as         

Hydroquinone $&gt;$ paranitrophenol $&gt;$ phenol