Question

In the laboratory preparation of hydrogen, mention the following –
a) chemicals used
b) balanced equation
Why dilute H2SO4 is not used in the preparation of CO2 from CaCO3?​

Answer 1

(a) CaCO_3+2HCl\ →\ CaCl_2+CO_2+H_2O

(b)

(i) Concentrated H_2SO_4 absorbs moisture from the gas in the washer bottle.

(ii) The prepared gas is CO2 which does not collect over water because it is soluble in water.

(iii) Dilute sulphuric acid when used as a reactant with calcium carbonate forms a coating of insoluble calcium sulphate and the reaction stops after a while. CaCO_3+H_2SO_4\ →\ CaSO_4+CO_2+H_2O