Mass Transfer - Engineering

Q1:

A minimum boiling azeotrope is exemplified by

A toluene-benzene

B acetone-carbon disulphide

C water-isobutyl alcohol

D none of these

ANS:B - acetone-carbon disulphide

A minimum boiling azeotrope is exemplified by the binary mixture of water and isobutyl alcohol. In a minimum boiling azeotrope, the boiling point of the mixture is lower than the boiling point of either pure component. For the water-isobutyl alcohol system, the azeotropic mixture has a lower boiling point than the boiling points of pure water and pure isobutyl alcohol. At the azeotropic composition, the vapor phase has the same composition as the liquid phase, resulting in constant boiling behavior. This occurs due to the formation of hydrogen bonds between water and isobutyl alcohol molecules, which alters the vapor pressure of the mixture, resulting in a minimum boiling azeotrope. So, the correct option is "water-isobutyl alcohol."