7th Class Science Physical and Chemical Changes Question Bank Physical and Chemical Changes

  • question_answer
    Which of the following statements is correct?

    A) When coal is burnt no new substance is produced

    B) Rust is not formed in the absence of air or oxygen

    C) The fizz that comes out when a soda bottle is opened is due to a chemical change.

    D) Respiration is a physical process

    Correct Answer: B

    Solution :

    For formation of rust both water vapour and oxygen are essential.


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