Some of the solid BaCrO₄ dissolves to form Ba²⁺ and CrO₄^2- ions.

Adding HCl converts CrO₄^2- to Cr₂O₇^2- which causes more BaCrO₄ to dissolve to replenish the lost chromate ions.

Is BaCr₂O₇ soluble in water?

  Yes     No