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NDA 1 2025 GAT, question 80

Topic: Chemistry

Q80

Which one of the following statements about a compound is NOT correct?

  1. (a) A compound is a substance composed of two or more elements, chemically combined in a fixed proportion
  2. (b) Properties of a compound are different from its constituent elements
  3. (c) A compound is an impure substanceCorrect answer
  4. (d) The constituents of a compound can be separated only by chemical or electrochemical reactions

Solution.

Answer: (c) A compound is an impure substance

  1. A compound is a pure substance with a definite composition, so calling it impure is incorrect.
  2. Its chemically bonded constituents produce properties different from those of the free elements; separating them requires chemical change, unlike separating a physical mixture.