Hi, I have searched rigorously for a solution to this problem but I seem to get inconclusive answers. I want to find the percentage purity of iron in cast iron and the best way to go about this is a redox titration. The first step is to reduce the Iron to Fe2+ . I intend to do this by reacting it with Sulphuric Acid and forming FeSO4. The only thing is, will cast iron react with dilute sulphuric acid (<1M) or does it require concentrated acid (>1M)? I know with conc. acid the resulting products are FeSO4 + SO2 + H2O and just FeSO4 + H2 with dilute acid. Any advice/feedback would be much appreciated.