Question

It is observed that Calcium on reaction with water floats on its surface. Explain why it happens. Also write a balanced chemical equation for the reaction that occurs. What happens when the aqueous solution of the product of this reaction reacts with Carbon dioxide gas? Write a balanced chemical equation for the reaction.

Answer 1

1. Because the reaction between calcium and water generates hydrogen gas, which sticks to the surface of the calcium metal and causes it to float, calcium floats on the water's surface when it reacts with it. The balanced chemical equation for the reaction of calcium with water is:
   \[\ce{Ca_{(s)} + 2H2O_{(l)} -> Ca(OH)2_{(aq)} + H2_{(g)}}\]
2. Calcium hydroxide in an aqueous solution interacts with \[\ce{CO2}\] to generate calcium carbonate and water. The balanced chemical equation for this reaction is:
   \[\ce{Ca(OH)2_{(aq)} + CO2_{(g)} -> CaCO3_{(s)} + H2O_{(l)}}\]