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

Why Calcium Floats: Calcium reacts with water to produce calcium hydroxide and hydrogen gas. The hydrogen gas bubbles stick to the surface of calcium, making it float.
Balanced Chemical Equation for the Reaction:
\[\text{Ca (s)} + 2\text{H}_2\text{O (l)} \rightarrow \text{Ca(OH)}_2 \, (\text{aq}) + \text{H}_2 \, (\text{g}).\]
Reaction with Carbon Dioxide:
The calcium hydroxide solution reacts with carbon dioxide to form calcium carbonate (\(\text{CaCO}_3\)), which appears as a white precipitate.
\[\text{Ca(OH)}_2 \, (\text{aq}) + \text{CO}_2 \, (\text{g}) \rightarrow \text{CaCO}_3 \, (\text{s}) + \text{H}_2\text{O (l)}.\]