Sulfur dioxide gas (SO2) is prepared in the laboratory in following ways :
Theory : Sulfur dioxide gas is prepared in the laboratory by heating copper turnings with conc Sulfuric acid (H2SO4) .
Reaction involved :
Procedure : As shown in the figure, some copper turnings are kept in the round bottom ask which is fitted with thistle funnel and delivery tube.
The other end of delivery tube is kept in a absorption bottle containing conc sulfuric acid. Conc Sulfuric acid is poured in the thistle funnel which reaches to the round bottom ask to start the reaction. Again , one end of delivery tube is kept in absorption bottle and other end is introduced to an erect gas jar for the collection of sulfur dioxide gas by upward displacement of air.
The copper or flask is heated. On doing so the reaction between acid and copper takes places and sulfur dioxide gas (SO2 ) is produce in the ask. The SO2 gas produced is not pure so it passed through absorbtion bottle containing con H2SO4 to remove moisture from the gas as H2SO4 is a great dehydrating agent. After removement of moisture finally, SO2 gas is collected in the gas jar by upward displacement of air.
Test : The presence SO2 gas can be tested by introducing potassium manganese to the mouth of the jar. If it discolourizes then we can know that SO2 is collected in the jar.
