One solution is poured into six different glasses and they become different colors
name: Solution of NH4Fe(SO4)2*12H2O reacts with SCN-, Ba2+, [Fe(CN)6]3-, HSO3- ions, tannic and tartaric acid
Fe3+ + SCN- → [Fe(SCN)]2+
Ba2+ + SO42- → BaSO4↓
Fe3+ + [Fe(CN)6]3- → Fe[Fe(CN)6]
Fe3+ + C76H52O46 (tannic acid) → Ferrum tanates
Fe3+ + C4H6O6 (tartaric acid) → Fe2(C4H4O6)3
Fe3+ + 3HSO3- → Fe(HSO3)3
The solution of ammonium iron(III) sulfate contains Fe3+ and SO42- ions. There are thiocyanate, barium, ferricyanide, sulfide ions, tannic and tartaric acids in the glasses.
Potassium thiocyanate reacts with Fe3+ ions and forms a dark-red colored solution, which contains [Fe(SCN)]2+ ions.
Barium and sulfate ions form the crumbly barium sulfate precipitate. The final solution looks dense and light-yellow colored.
Potassium ferricyanide with Fe3+ ions forms a red colored complex Fe[Fe(CN)6] solution.
Tannic acid is a big molecule with many OH-groups and it coordinates with Fe3+. The deep -blue colored solution looks like ink.
Tartaric acid coordinates with Fe3+ ions and forms a yellow complex.
HSO3- ions are produced from sodium bisulfite and a red solution of iron(III) hydrogen sulfite solution is formed.