The correct option is (c).
Explanation
Changes in matter are broadly classified into physical and chemical changes. A physical change affects only the physical properties (such as state, shape, or size) without altering the chemical composition. A chemical change results in the formation of new substances with different chemical properties.
Statement-wise Analysis:
- Statement 1 is Incorrect. The burning of coal is not a physical change. It is an irreversible process where the original substance (coal) is chemically altered and cannot be recovered. A mere change of state (like melting ice) is physical, but burning involves a reaction.
- Statement 2 is Correct. Burning is a combustion reaction, which is a specific type of chemical change. It is characterized by the release of energy in the form of heat and light (exothermic reaction). The production of heat is a strong indicator of a chemical reaction in this context.
- Statement 3 is Correct. The definitive proof of a chemical change is the formation of new substances. When coal (primarily Carbon) burns in the presence of Oxygen, it forms Carbon Dioxide ($CO_2$), a new substance with properties distinct from coal and oxygen.
Reaction: $C + O_2 \rightarrow CO_2 + \text{Heat} + \text{Light}$
Key Takeaway:
Burning (combustion) is always a chemical change because it involves the breaking and making of chemical bonds, results in new products (like $CO_2$), and releases energy.