2Na3[IrCl6] + 6H2SO4 → Ir2(SO4)3 + 3Na2SO4 + 12HCl
Sodium hexachloridoiridate(III) react with sulfuric acid to produce iridium(III) sulfate, sodium sulfate and hydrogen chloride. Sulfuric acid concentration less 40%. The reaction takes place in a boiling solution.