sentences:  This is titrated acidimetrically along with “free” hydroxyl present and the carbonate content (as a second endpoint).The second titration is preceded by the automatic addition of fluoride solution.The alumina-tartrate complex is broken in favour of the formation of an aluminium fluoride complex and the concomitant release of three moles of hydroxyl for each mole of aluminium present, which are then titrated acidimetrically.