Correct Option
The correct option is (c).
Explanation
A chemical compound is a pure substance composed of two or more different elements that are chemically bonded together. The formation of a compound involves a chemical change, resulting in a substance with a specific composition and structure.
Statement-wise Analysis
Statement 1 is Incorrect.
A compound is composed of elements combined in a fixed proportion by mass, in accordance with the Law of Definite Proportions. A substance composed of elements mixed in any proportion is defined as a mixture, not a compound.
Statement 2 is Correct.
The physical and chemical properties of a compound are entirely distinct from those of its constituent elements. For example, water (H2O) is a liquid that extinguishes fire, whereas its constituents, hydrogen (combustible) and oxygen (supporter of combustion), are gases with completely different properties.
Statement 3 is Correct.
Since the constituents of a compound are held together by strong chemical bonds, they cannot be separated by physical methods (such as filtration, evaporation, or magnetic separation). They can only be separated into their constituent elements by chemical or electrochemical reactions (e.g., electrolysis of water).
Key Takeaway
Compounds are characterized by a fixed chemical composition, properties distinct from their constituent elements, and the requirement of chemical methods for separation. Mixtures retain the properties of their components and can be separated by physical means.