How is: (a) methane and (b) ethane prepared in the laboratory?
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Each Part: 1 Mark
(a) A mixture of sodium ethanoate (sodium acetate) and soda lime is taken in a hard glass test tube and heated. The gas collected by the downward displacement of water as CH4 is slightly soluble in water. The reaction involved is: CH3COONaSodiumacetate+NaOHCaO,300∘C−−−−−−−→CH4Methane+Na2CO3 Soda lime is a mixture of caustic soda (NaOH) quicklime (CaO) in which CaO keeps the NaOH dry.
(b) To prepare ethane, a mixture of sodium propionate and soda lime is taken in a hard glass test tube and heated. C2H5COONaSodiumpropionate+NaOHCaO−−−→300∘CNa2CO3+C2H6Ethane↑