Burning of oil in a wick is a chemical change give reason
Answers
The burning of oil is a chemical change, It is a simple combustion reaction.
OIl is made of hydrocarbons. all hydrocarbon when ignites forms carbon dioxide and water.Even the wick is also made of cotton which is cellulose. Cellulose is nothing but carbohydrates, which on combustion gives Carbon dioxide and water.
So when oil is burnt with wick it is chemical reaction.
If we want to detect the formation of Carbon dioxide, we can pass the gas through lime water which solution of calcium hydroxide. the limewater will turn into milky white due to formation of calcium carbonate which is insoluble in water.
Other way is to cover the wick container with cold glass, if the oil is getting completely burnt we might get few drops of water. But it is tough due to heat generated by combustion.
Another method is put a glass rod above the flame. It will get black because of deposition of carbon, condition applied if oil is combusted fully.