“Sulfur dioxide“ from the “Sulfur and nitrogen dioxides“ set
Channel: MEL Chemistry
Date: 2018-04-19

Perform this amazing experiment at home with MEL Science: https://melscience.com/en/experiments/so2no2-sulfurdioxide/

Safety
* Put on protective gloves and eyewear.
* Conduct the experiment on the plastic tray and in a well-ventilated area.
* Keep a bowl of water nearby when working with fire.

Disposal
* Dispose of solid waste together with household garbage.
* Pour solution down the sink.
* Wash with an excess of water.

Step-by-step instructions
1. Coat the paper flower with the acid-base indicator thymol blue.
2. To create sulfur dioxide SO₂, combine sodium metabisulfite Na₂S₂O₅ and citric acid to cause a chemical reaction.
3. The reaction speeds up when heated. Sulfur dioxide dissolves in the water imbued in the flower, forming sulfurous acid. The acid-base indicator reacts to this and changes colors.
4. To stop the flow of gas, blow out the candle and add water to the solution.
5. With exposure to air, some of the sulfur dioxide vaporizes and the indicator turns orange.