Question

Candles contain paraffin wax, a hydrocarbon. When a test tube filled with cold water is placed over a burning candle, condensation appears on the outside of the test tube. If a large Kari’s inverted over the burning candle, and the gas in the jar is bubbled via suction through a solution containing calcium hydroxide, CA(OH)2, a white precipitate of CaCO3 is observed. Explain these observations based on the products of combustion.

Answer 1

ANSWER:

Generally, hydrocarbon contains carbon and hydrogen. Oxygen, nitrogen, sulphur etc are also found in less quantity.

On burning a hydrocarbon, carbon-dioxide and water are produced. reaction is as follows-

Thus, by putting cold water above burning candle shows condensation and passing the evolved gas by calcium hydroxide solution gives white precipitate of calcium carbonate.