Task: Text Categorization
Input (English): Question: The solubility of calcium fluoride in a solution of pH <3 is higher than in pure water due to: 
 Options:  <0> The absence of reactions of formation of hydroxylated calcium complexes at these pH values. <1> The lower hydration capacity of the precipitate particles at these pH values. <2> The absence of reactions of formation of soluble complexes of calcium and fluoride at these pH values. <3> The complex formation reactions of the Ca2 + ion with the hydronium. <4> The protonation reaction of the fluoride anion.
Output (English): chemistry