When a compound is soluble in a dilute mineral acid, is it necessary that it is also soluble in that concentrated acid?

For example, Barium Phosphate is soluble in dilute mineral acids. Does that also mean that it is also soluble in concentrated form of those acids?




Well. Barium phosphate $\ce{Ba3(PO4)2}$ is not soluble at all in sulfuric acid $\ce{H2SO4}$ solutions, whatever their concentrations, because it forms barium sulfate $\ce{BaSO4}$ which is an insoluble compound. On the other hand it is soluble in diluted solutions of hydrochloric acid, according to $$\ce{Ba3(PO4)2 + 6 HCl -> 3 BaCl2 + 2 H3PO4}$$ Unfortunately it is not soluble in concentrated $\ce{HCl}$ solutions, because it produces some barium chloride $\ce{BaCl2}$ which has the strange property of being insoluble in concentrated $\ce{HCl}$ solutions, as the solubility product of $\ce{BaCl2}$ is exceeded.


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