Question

On burning candles it undergoes both physical and chemical change?
  A. Yes
  B. No
  C. Maybe
  D. Data insufficient

Answer 1

Hint: When candle burns it changes into wax by changing its physical state and at the same time the wax tries to combine with the atmospheric oxygen and convert into carbon dioxide, light and heat.

Complete answer:
1. It is both physical & chemical change as the physical change occurs when there is no modification of the substance’s chemical composition.
and when a candle is burnt and the wax melts changing from solid to liquid state is referred to as physical change.
2. Burning of candle melts the wax and hence the physical state of wax has changed from solid to liquid.
3. Then the wax combines with the oxygen in the atmosphere and changes to $C{O}_2$ heat & light.
4. Hence both physical and chemical changes take place with the burning of the candle.
Let's look at the concepts deeply how it occurs step by step:-
we can see the physical change. When the candle burns, the wax slowly melts & the candle gets smaller. The wax will drip onto the candle and stick to it. When this wax forms back into a solid and stays on the candle, again physical change takes place.
It's very tough to observe the chemical change. As the heat produced by the candle consumes both the oxygen around it, as well as the fuels coming from the flame. This will then lead to carbon dioxide emissions produced by the flame, which by the way should never be inhaled. Now we can observe the chemical change taking place in the whole process.
Hence we can say that both the physical and chemical change takes place during the burning of candles.

Thus the Correct option is (A).

Note:
Physical change means change in physical state like from solid to liquid or liquid to gas and chemical change refers to change in the chemical composition of any substance.