What is the reason for the different solubility of organic acids in water? For example, acetic and benzene?

Let us consider the interaction of organic acids using the example of the reaction of acetic acid and zinc.

Zn + 2CH3– C = O-OH → (CH3C = O-O) * 2 Zn + H2.

And now let’s look at the example of the interaction of benzene acid and water. If you mix a little water and benzene acid, then nothing happens, the acid does not dissolve in the water. For the reaction to proceed, it is necessary to heat this solution, then the acid dissolves completely in water, and when the solution cools down, the acid will precipitate again.

Thus, we can say that the radical on the polar O-H bond in the acid residue plays a key role in the solubility of organic substances, therefore, the larger the radical, the worse the solubility of the substances.