This plateau is where a phase change occurs. Likely, this cooling curve observes the changing of a liquid into a solid (so that the temperature is quantifiable). As something cools, it’s losing energy to the surroundings; when a phase change occurs, like liquid to solid, energy isn’t lost directly from the atom, but instead the energy maintained by free motion of the atom is used. This lack of motion reduces it into a lattice (all while maintaining a constant internal energy), finalizing the phase change, after which energy is lost directly from the atom again.
Pyridine will neutralize the acid by-product of the reaction.
Explanation:
In the esterifications, hydrochloric acid is released as a by-product that reacts directly with the pyridine in the medium to give the pyridine hydrochloride.
