Question

Q2. In the laboratory preparation of carbon dioxide by the action of a dilute acid on a metallic carbonate, (i) Why carbon dioxide prepared in this reaction is not collected over water? (ii) Why sulphuric acid is not used in this reaction? (iii) Name the metal carbonate which is used in this reaction.​

Answer 1

Answer:

Dilute sulphuric acid reacts with calcium carbonate. But it is not used  because the calcium sulphate which is formed during the reaction is  insoluble in water. It covers the marble chips and stops the reaction.

1. The prepared gas is CO2 which does not collect over water because it is soluble in water.
2. In the presence of a dilute acid, KI would produce HI. If the acid used is sulphuric acid, the HI gets used up to produce I2 gas. As a result, the action of alcohol on acid to produce alkyl iodide cannot occur. Therefore, sulphuric acid is not used for this reaction.
3. Carbon dioxide,water