Hydrogen is basically prepared by action of dilute acids On metals.
Dilute Hydro chloric acid is added To zinc granules. The hydrogen produced is then passed through anhydrous calcium chloride or concentrated sulphuric acid. The hydrogen collected by upward delivery because it is lighter than air. If the reaction is too slow Copper (II) Sulphate solution can be added to speed up the solution.
Zn (s)+ 2HCl (aq)———ZnCl2 (aq)+ H2(g).