Question

Use two equations,one to describe the laboratory preparation of co2 and the other to confirm the presence of the gas.

Answer 1

Carbon dioxide is produced whenever an acid reacts with a carbonate. This makes carbon dioxide easy to make in the laboratory. Calcium carbonate and hydrochloric acid are usually used because they are cheap and easy to obtain.

CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + CO₂(g) + H₂O(l)

The most effective way to test for CO₂ is to bubble the gas through "limewater", a diluted solution of calcium hydroxide (slaked lime). When you bubble carbon dioxide through the solution, it forms a solid precipitate of calcium carbonate – chalk or limestone.

Ca(OH)₂ + CO₂ → CaCO₃ + H₂O