Write the reaction equation: K-K2O-KOH-K2CO3-KHCO3-K2CO3-CaCO3

1) 4K + O2 = 2K2O (when potassium interacts with oxygen, potassium oxide is formed);

2) K2O + H2O = 2KOH (when potassium oxide interacts with water, potassium hydroxide is formed);

3) 2KOH + CO2 = K2CO3 + H2O (when potassium hydroxide interacts with carbon dioxide, potassium carbonate and water are formed);

4) K2CO3 + H2CO3 = 2KHCO3 (when potassium carbonate interacts with carbonic acid, potassium bicarbonate is formed);

5) KHCO3 + KOH = K2CO3 + H2O (when potassium bicarbonate interacts with potassium hydroxide, potassium carbonate and water are formed);

6) K2CO3 + Ca (OH) 2 = CaCO3 + 2KOH (when potassium carbonate interacts with calcium hydroxide, calcium carbonate and potassium hydroxide are formed).