Question

State one instance where water undergoes physical change and one in which it undergoes a chemical change.

Answer 1

Changes of matter can be classified into two, i.e.., physical and chemical changes

Physical changes	Chemical changes
Changes which involve physical properties like colour, appearance etc..,	Changes which involve chemical properties like nature of bonding, energy, etc.
Generally, no new substances are formed here	Generally, new substances are formed here
No energy or heat change involved	Energy or heat change involved
Examples: Melting of ice	Examples: Electrolysis of water

By considering the properties of physical and chemical changes, we can write the instances where water undergoes a physical and chemical change as:

Boiling of water is an example of physical change which involve state change (liquid to gaseous state)

Electrolysis of water is a chemical change where water is broken down to produce hydrogen and oxygen which are different substances.