UPSEE Solved Model Paper 6

Concentrated sulphuric acid is often used as a dehydrating agent (to remove water). When sugar or sucrose, C12H22O11 is treated with con. H2SO4, the sugar changes from white to dark brown and then to black due to the formation of carbon. The reaction is shown below

Hence in the reaction between con. H2SO4 and sugar, sugar becomes black due to dehydration.