Burning a candle does not produce oxygen; instead, it consumes oxygen. The process of burning a candle involves a chemical reaction called combustion, where the candle's wick, which is usually made of cotton or a similar material, reacts with the heat and flame to release energy. The primary components of a candle are wax (usually made of hydrocarbons) and a wick.
When you light a candle, the heat from the flame melts the wax near the wick. The liquid wax is drawn up the wick by capillary action. As the liquid wax reaches the top of the wick, it gets vaporized by the heat from the flame, turning into a gaseous state.
Once in the gaseous state, the hydrocarbon molecules in the wax react with oxygen present in the surrounding air. This chemical reaction releases energy in the form of heat and light. The products of this combustion process are primarily carbon dioxide (CO2) and water vapor (H2O).
The chemical equation for the combustion of hydrocarbons, like those found in candle wax, is typically as follows:
Hydrocarbon (CxHx) + Oxygen (O2) → Carbon Dioxide (CO2) + Water Vapor (H2O) + Heat
So, when a candle burns, it uses oxygen from the surrounding air to produce carbon dioxide and water vapor, not oxygen. If the candle were somehow creating oxygen, it would contradict the fundamental principles of chemistry and conservation of mass.