Multiple choice

Which of the following is not a chemical reaction?

  1. Burning of paper

  2. Digestion of food

  3. Conversion of water into steam

  4. Burning of coal
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C Correct answer
Explanation

Conversion of water to steam (evaporation/boiling) is a physical change - only the state of matter changes from liquid to gas, not the chemical composition. The other options (burning paper, digestion, burning coal) all involve chemical reactions forming new substances.

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