More soluble in acid than in water? why?

The examples given, and many more, do not "dissolve" in acids. They undergo a chemical reaction with the acid to form a completely different product that is water soluble. For instance, take Fe(OH)3. If you add this to HCl you will see that the iron hydroxide reacts to produce FeCl3 and water. The FeCl3 is water soluble. If you were to evaporate the water away, you would not recover your original Fe(OH)3, but you would get the chloride.