You try to compare compound - benzoic acid with pyridinium unknown salt.
Benzoic asid is poorly soluble in water. Its sodium salt is much more soluble. Solubility of benzoic acid in strong acid solution will be lower from that in water
Concerning Pyridinium salt - it is good soluble in water, in HCl also, but when you have pyridinium hydrochloride and put it into solution of HCl, solubility of Pyr.HCl can be slightly lower. When you mix pyridinium salt with NaOH, a neutralization reaction will occur and free pyridine will form. Pyridine itself is miscible with water, hence you cannot determine its solubility.
Poor question!