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NDA 2 2025 GAT, question 101

Topic: Chemistry

Q101

Which one of the following statements is NOT correct ?

  1. (a) The interconversion of states of matter is a physical change
  2. (b) During burning of a candle, both chemical and physical changes take place
  3. (c) During a physical change, the chemical composition of molecules changesCorrect answer
  4. (d) Rusting of iron is a chemical change

Solution.

Answer: (c) During a physical change, the chemical composition of molecules changes

  1. A physical change preserves chemical identity.
  2. Therefore the claim that molecular chemical composition changes during a physical change is false.
  3. Candle wax both melts physically and burns chemically, while rusting is chemical.