Candles are extinguished with an invisible substance.
name: The experiment shows carbon dioxide gas being poured to extinguish a candle flame.
When vinegar and baking soda come into the contact they react with the production of CO2 gas:
2CH3COOH + Na2CO3 → 2CH3COONa + CO2 + H2O
CO2 does not support burning and can be used to extinguish fire. The gas is heavier than air and settles at the bottom of the glass. It can be easily poured out of it like a liquid. When CO2 is poured on the candle it prevents burning.