Question

In preparing your soap, you dissolved 12.5 g of sodium hydroxide in 32.0 mL of de-ionized water. Your product was a solid cake of soap. What happened to the water you added when preparing your soap during the course of the experiment?

Answer 1

Explanation:

The generated Na+ and OH-ions are immediately surrounded by molecules of water (typically 6, each). There is the development of the exothermic hydration sphere for each ion. It seems as though there is negative overall energy of dissolving solid NaOH.

Now, since this dissolution is exothermic the temperature of the mixture rises.