Chlorine — the gas artist
How chlorine can change the color of a drawing
Usually, when we talk about artists, we think of people like Dali, Picasso and Munch, but among the chemical elements there are those who can draw!
Warning! Observe safety rules when working with these substances. Wear protective gloves, glasses, and a mask.
- sodium chloride;
- sodium hydrogen sulfate;
- manganese(IV) oxide;
- potassium iodide solution;
- thymol blue solution;
- heating device;
- filter paper;
- cotton swab or brush.
Mix sodium chloride, sodium hydrogen sulfate, manganese(IV) oxide and water in a glass and mix thoroughly. Draw some patterns on a filter paper with solutions of potassium iodide or thymol blue. Place the filter paper on top of the beaker of sodium chloride solution and heat the beaker gently. Gradually, the drawings change colors!
When a mixture of sodium chloride, sodium hydrogen sulfate, manganese oxide(IV) and water is heated, chlorine gas is released. The released gas dissolves in the water from the solutions the drawings are made of. When a solution of potassium iodide comes into contact with chlorine, as a more active halogen, chloride ions displace iodine ions, and molecular iodine is released and the pattern turns brown. When chlorine dissolves in the water of the thymol blue solution, it disproportionates, or it is oxidized and reduced to hydrochloric HCL and hypochlorous HOCl acids, which change the acidity of the solution and thymol blue changes from orange to purple color.
A similar experiment is included in the “Hydrogen and Chlorine” set from the MEL Chemistry subscription!