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?

Based on the fundamental principles of chemistry (NCERT Class 9):

• Statement 1 is correct: An element is a basic form of matter that cannot be broken down into simpler substances by chemical reactions.
• Statement 2 is incorrect: A compound consists of two or more elements chemically combined in a fixed (definite) proportion. It is mixtures that have variable compositions. While compounds can be broken down into elements, they must be broken down by chemical or electrochemical reactions.
• Statement 3 is correct: A solution of sulphur in carbon disulphide is a homogeneous mixture because the composition is uniform throughout and the components cannot be seen separately.

Since the question asks for the statement(s) that are not correct, only statement 2 is the answer.