When 38.0 mL of 0.1250 M H2SO4 is added to 100. mL of a solution of PbI2, a precipitate of PbSO4 forms. The PbSO4 is then filtered from the solution, dried, and weighed. If the recovered PbSO4 is found to have a mass of 0.0471 g, what was the concentration of iodide ions in the original solution?
◦ 3.10 × 10–4 M
◦ 1.55 × 10–4 M
◦ 6.20 × 10–3 M
◦ 3.11 × 10–3 M
◦ 1.55 × 10–3 M