CDS 2026 (I) General Knowledge, question 22

Topic: Chemistry

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Q22

Consider the following statements regarding matter :

  1. Elements cannot be broken down into simpler substances.

  2. A compound has variable composition and can be broken down into elements.

  3. The solution of sulphur in carbon disulphide is an example of a homogeneous mixture.

Which of the statements given above is/are not correct ?

  1. (a) 2 onlyCorrect answer
  2. (b) 1 and 3
  3. (c) 3 only
  4. (d) 1 and 2

Solution.

Answer: (a) 2 only

  1. Statement 2 is incorrect: a compound has a fixed composition, whereas a mixture may have variable composition.
  2. Elements cannot be decomposed by ordinary chemical methods, and sulphur dissolved in carbon disulphide forms a homogeneous solution.
  3. The qualification “chemical methods” matters because nuclear reactions can transform elements.