Reaction rates. Powdered iron is placed in two test tube with 1M solution of sulfuric acid (H2SO4, left) and hydrochloric acid (HCl, right) at room temperature. Iron (Fe) reacts with the acids producing hydrogen bubbles. The respective reactions are: Fe + H2SO4 -> FeSO4 + H2 and Fe + HCl -> FeCl2 + H2. Both acids are classified as strong acids. The reaction with H2SO4 proceeds more vigorously than with HCl since it produces twice as many hydronium ions (H3O+) for the same molar concentration.