A 0.2334-g quantity of primary standard NaCl is dissolved in 250.00 mL. A 10.00-mL aliquot of this solution consumes 14.32mL of a silver nitrate solution before reaching the end point in a Fajans titration. A chloride solution, prepared by dissolving 0.2789 g of an unknown sample in 250.00mL as well as taking a 10-mL aliquot of the resulting solution, requires 11.21mL of the same silver nitrate solution to reach the end point. Explain what percentage chloride (w/w) does the unknown contain?