Heat of Reaction Experiment, High school level

[bethanyd]

Homework Statement
I am working on a correspondence grade 12 Chemistry Course and I am confused by one question. I did an experiment involving hydrochloric acid (HCl) and sodium hydroxide (NaOH). Here is the question:
"In a reaction, Na+ ions are separated from OH- ions, a process of dissociation that absorbs energy, yet, in the end, heat was liberated by the overall process. Explain."

This has been asked before on this forum but there was not really a clear answer posted so I thought perhaps we could discuss it again. Here is the archived thread: https://www.physicsforums.com/archive/index.php/t-77030.html

The attempt at a solution
So I understand that, since the reaction was exothermic, something other than the breaking of the NaOH bonds must have occurred which took less energy and thus released the excess energy in the form of heat. I do not quite understand what happened that would have taken so much less energy. Would the following be a correct and reasonable answer: "The reorganization and formation of water took much less energy and resulted in heat being released." ?

 

[symbolipoint]

The solvated proton from the acid and the solvated hydroxide from the base are less stable (and have the potential to react...) than the water which results from their combining. The water is more stable than the separate ions. Energy is released into the environment upon this neutralization, and the increase in temperature can be observed (and measured).

 

[Blueshift5]

Your answer is correct and reasonable. In this reaction, HCl and NaOH react to form water (H2O) and sodium chloride (NaCl). The process of dissociation, where the Na+ and OH- ions are separated, does require energy. However, the formation of water from the hydrogen and hydroxide ions releases a much larger amount of energy, resulting in an overall exothermic reaction. This excess energy is released in the form of heat. So, your explanation of reorganization and formation of water taking less energy and resulting in heat being released is accurate.