Glass Contamination Problem?

Glass is a notorious source of metal ion contamination. Three glass bottles were crushed and sieved to collect 1 mm pieces. To see how much Al3+ could be extracted, 240. mL of a 0.05 M solution of the metal-binding compound EDTA was stirred with 0.50 g of the 1 mm glass particles in a polyethylene flask. The Al content of the solution after 2 months was 5.2 μM. The total Al content of the glass, measured after completely dissolving some glass in 48 wt% HF with microwave heating, was 0.80 wt%. What fraction of the Al was extracted from the glass by EDTA? (Enter your answer to 5 decimal places.)