The formula of chromium chloride is CrCl3 and the formula forsilver chloride is AgCl. The relevant formula unit masses are158.36 for chromium (III) chloride and 143.32 for silver chloride.The gram atomic masses of chlorine, chromium, and silver are35.453, 51.996, and 107.866 respectively. Therefore, the massfraction of chloride in chromium (III) chloride is[3(35.453)/158.36] or 0.671628 and the mass fraction of chloride insilver chloride is 35.453/143.32 or 0.24737. Therefore, to form75.0 g of silver chloride, (0.24737)(75.0) or 18.55 g of chlorideis needed, and this amount of chloride is contained in 18.55/0.6716or 27.6 g of chromium (III) chloride, to the justified number ofsignificant digits.