Plz choose the option
Dear Student,
(i) Burning of a matchstick is a chemical change. Because once the match stick is burnt it cannot be reversed and a new substance is formed during the process.
(ii) Melting of ice cream is a physical change and a reversible process. Because on heating ice cream melts from solid to liquid state and the process can be reversed by cooling in a refrigerator.
(iii) Crushing of glass is a physical change because the chemical composition of glass does not change on breaking but it is an irreversible process because the glass has to melt again and reform to get the glass again hence the process cannot be reversed easily.
(iv) Lighting an electric bulb is a physical and reversible change since the process can be reversed simply by turning off the switch and the chemical composition of the bulb does not change during the process.
Option (iii) is correct
Regards
(i) Burning of a matchstick is a chemical change. Because once the match stick is burnt it cannot be reversed and a new substance is formed during the process.
(ii) Melting of ice cream is a physical change and a reversible process. Because on heating ice cream melts from solid to liquid state and the process can be reversed by cooling in a refrigerator.
(iii) Crushing of glass is a physical change because the chemical composition of glass does not change on breaking but it is an irreversible process because the glass has to melt again and reform to get the glass again hence the process cannot be reversed easily.
(iv) Lighting an electric bulb is a physical and reversible change since the process can be reversed simply by turning off the switch and the chemical composition of the bulb does not change during the process.
Option (iii) is correct
Regards