A piece of wood becomes black when conc. H2so4 is poured on it. give reason.
Conc. H2SO4 is dehydrating agent.It dehydrates the cellulose (the chief constituent of wood) to carbon and water.The formation of carbon makes the wood black when conc. H2SO4 is poured on it.
[C6H5O10]n → 6[C]n + 5[H2O]n
cellulose