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Questions 2.1(e)

  1. Describe the observations made when a burning sodium or potassium metal is lowered into a gas jar full of dry oxygen gas
  2. Write chemical equations for the reactions between
    1. lithium and oxygen
    2. sodium and oxygen
    3. potassium oxygen


Answers to Questions 2.1(e)

  1. Alkali metals burn in oxygen gas with bright flames (yellow for sodium) and lilac for potassium) to produce white solids (oxides) which completely dissolve in water to form colorless solutions (hydroxides). The solutions turn red litmus blue; they are alkaline.

  2. 4Li(s)   +   O2(g)   ⟶  2Li2O(s)
    4Na(s)   +   O2(g)  ⟶   2Na2O(s)
    4K(s)   +   O2(g)  ⟶   2K2O(s)