Which of the following is an example of a physical as well as a chemical change?
Which of the following is an example of a physical as well as a chemical change?
The correct option is B Burning of candle
Among the given examples only burning of candle is an example which involves both physical as well as chemical change. It is a physical change because on heating, the candle wax melts and again turns into solid wax on cooling. It is a chemical change because new substances like carbon dioxide, carbon soot, water vapour, heat and light are produced in this process.
Photosynthesis is a chemical change because in this process a new substance is formed and it is irreversible.
Beating of aluminium to make foil and dissolving salt in water are both physical changes because in both the processes no new substance is formed. For instance, aluminium shows the same set of chemical properties even if it has been turned into a foil.
Burning of candle
Among the given examples only burning of candle is an example which involves both physical as well as chemical change. It is a physical change because on heating, the candle wax melts and again turns into solid wax on cooling. It is a chemical change because new substances like carbon dioxide, carbon soot, water vapour, heat and light are produced in this process.
Photosynthesis is a chemical change because in this process a new substance is formed and it is irreversible.
Beating of aluminium to make foil and dissolving salt in water are both physical changes because in both the processes no new substance is formed. For instance, aluminium shows the same set of chemical properties even if it has been turned into a foil.
