Question

Stainless steel is an alloy of iron, chromium, and nickel, having approximately 15.5% chromium. In an assay to discover how much chromium is present, the steel is oxidize in acid to form chromate ion. The resulting solution is treated with excess lead(II) ion to produce a stable precipitate of lead chromate, according to the following reaction:

CrO42-(aq) + Pb2+(aq) ==> PbCrO4(s)

How many mL of 14.2% lead (II) nitrate solution (density=1.36 g/mL) should be used to assure 50% excess Pb2+ for the reaction involving a 3.2922 gram stainless steel sample? Round your answer to the nearest whole mL.