This is not a chemical change:
1 Burning of wood
2 Rusting of iron
3 Melting of wax
4 Digestion of food

Correct option is C

Correct Answer: (c)
Explanation
A chemical change results in the formation of one or more new substances, whereas a physical change changes only the physical state or appearance without forming a new substance.
Analysis of the options:
· Burning of wood → Chemical change (new substances like ash, CO₂ are formed}.
· Rusting of iron → Chemical change (iron oxide is formed}.
· Melting of wax → Physical change (only change of state; composition remains the same}.
· Digestion of food → Chemical change (food is converted into simpler substances}.
Therefore, melting of wax is not a chemical change.
Hence, the correct answer is Option (c}.
Additional Information
Characteristics of a Physical Change:
· No new substance is formed.
· Usually reversible.
· Only physical properties (state, shape, size} change.
Characteristics of a Chemical Change:
· New substance(s] are formed.
· Usually irreversible.
· May involve heat, light, gas evolution, colour change, or precipitate formation.
Examples of Physical Changes:
· Melting of ice
· Boiling of water
· Sublimation of camphor
· Melting of wax
Examples of Chemical Changes:
· Burning of paper
· Rusting of iron
· Fermentation
· Digestion of food