question_answer 44)

    Which one of the following processes involve chemical reactions? (a) Storing of oxygen gas under pressure in a gas cylinder (b) Liquefaction of air (c) Keeping petrol in a China dish in the open (d) Heating copper wire in the presence of air at high temperature

Answer:

  (d) A chemical reaction is a change in which one or more substance (s) or reactant (s)react to form new substance (s) with entirely different properties.