Alkali Metals React with Oxygen

  1. Group 1 metals react with oxygen gas produces metal oxides. These metal oxides dissolve in water produces alkalis.

    Group 1 Metals + Oxygen Gas → Metal Oxide
  2. Lithium, sodium and potassium form white oxide powders after reacting with oxygen.
  3. The white powder is the oxide of lithium, sodium and postassium.
  4. When the white powder is dissolved in water, it produces a solution which turned red litmus paper blue. Which means, these oxides dissolve in water to form strong alkali.
  5. The reactivity increases down the group from lithium, sodium to potassium.

Lithium + Oxygen

4Li + O2→ 2Li2O

Dissolve in water

Li2O + H2O → 2LiOH

Lithium burns with red flame and produces white powder immediately after reaction.

Sodium + Oxygen

4Na + O2→ 2Na2O

Dissolve in water

Na2O + H2O → 2NaOH

Sodium burned with bright yellow flame, forming white powder immediately after reaction.

Potassium + Oxygen

4K + O2→ 2K2O

Dissolve in water

K2O + H2O → 2KOH

Potassium burned with very bright purplish flame, forming white powder immediately after reaction.


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