Conc. H_(2)SO_(4) is added followed by heating to each of the following test tubes labelled (I) to (IV). Identify in which of the above test tube the following change will be observed. Support your answer with the help of chemical equation: (a) formation of black substance (b) evolution of brown gas (c ) evolution of colourless gas (d) formation of a brown substance which on dilution becomes blue. (e) disappearance of yellow powder along with evolution of colourless gas.

Conc. H_(2)SO_(4) is added followed by heating to each of the followin

1.	Conc. H_(2)SO_(4) is added followed by heating to each of the following test tubes labelled (I) to (IV). Identify in which of the above test tube the following change will be observed. Support your answer with the help of chemical equation: (a) formation of black substance (b) evolution of brown gas (c ) evolution of colourless gas (d) formation of a brown substance which on dilution becomes blue. (e) disappearance of yellow powder along with evolution of colourless gas.
Answer» Solution :(a) `underset("White")(C_(12)H_(22)O_(11))rarr underset("Black substance")(12C)+11H_(2)O` (b) `2NaBr+2H_(2)SO_(4)rarr underset("Brown gas")(Br_(2)uarr)+Na_(2)SO_(4)+SO_(2)+2H_(2)O` (c ) `2KCl+H_(2)SO_(4)""underset("(Colourless gas")(2HCluarr+K_(2)SO_(4))` (d) `Cu+2H_(2)SO_(4)rarr CuSO_(4)+SO_(2)+H_(2)O` (e ) `3S+2H_(2)SO_(4)rarr underset("(Colourless gas)")(3SO_(2)uarr+2H_(2)O)`