Q.Sulphuric acid is a dehydrating agent. Justify with an example.

Concentrated sulphuric acid's very high affinity for water lets it remove not just free water but also the elements of water (H and O, in a 2:1 ratio) from organic compounds — dramatically demonstrated by the charring/blackening of sugar.

Concentrated sulphuric acid has an extremely strong affinity for water, making it an effective drying/dehydrating agent for gases (e.g. drying $Cl_2$, $CO_2$, $H_2$) that don't react with it. Its dehydrating power goes further: it can abstract hydrogen and oxygen atoms directly from organic compounds, in exactly the 2:1 ratio found in water, even when no free water is present in the compound. The classic demonstration is its action on cane sugar (sucrose, $C_{12}H_{22}O_{11}$): concentrated $H_2SO_4$ removes 11 molecules of water's worth of H and O atoms from the sugar molecule, leaving behind a spongy black mass of carbon and releasing heat (the reaction is strongly exothermic): $C_{12}H_{22}O_{11} \xrightarrow{\text{conc. }H_2SO_4} 12C + 11H_2O$ This charring re …