The red rose turns white.
name: Sulfur dioxide oxidizes the red pigment in rose petals.
Restore a rose | Sulphur | Chemistry
Free Range Chemistry 22 - Burning Sulphur with Rose
Sulphur dioxide is a very toxic gas. Perform this experiment only in a fume hood. Wear eye protection goggles and gloves.
Always follow general safety
recommendations. Please note that conducting chemistry
experiments you must comply with the relevant legal procedures in
S + O2 → SO2
2S + 3O2 → 2SO3
SO2 + red rose pigment → SO42- + reduced rose pigment (white)
- This experiment should be performed only in a fume hood.
- Place some sulfur into the ceramic cup.
- Put the cup into the large beaker.
- Prepare a red rose. Attach a wire to the flower’s stem.
- Hang the flower inside the beaker.
- Ignite the sulfur and cover the beaker with a glass.
- After a while take out the flower. The rose turns white.
Anthocyanins are common pigments of many flowers. The red color of rose petals is caused by their presence. When sulfur burns it produces sulfur dioxide and sulfur trioxide. Sulfur dioxide acts like a bleaching agent. It oxidizes anthocyanins and turns the rose white.