Question

Steam Distillation

1. True or false.

_____ a. Steam distillation would be the appropriate technique for separating a mixture of 1,2-ethanediol (elthylene glycol, bp 196 oC) and water. 1,2-Ethanediol is completely miscible in water.

_____ b. Steam distillation would be the appropriate technique for separating a mixture of p-dichlorobenzene (p 174 oC) and water. p-Dichlorobenzene is completely insoluble in water.

_____ c. The boiling point during steam distillation is always less than 100 oC.

2. Which kind of distillation is best under the following circumstances: simple distillation, fractional distillation or steam distillation?

a. Separating a mixture of bromobenzene and toluene.

b. Separating cinnamaldehyde from cinnamon bark.
c. Separating ethyl acetate from methyl violet.

Answer 1

1. True or False

a. False...Ethylene Glycol on mixing with Water forms Hydrogen Bonding (due to Polar OH group) which gives rise to Max. Boiling Azeotrpic Mixture. Therefore Steam Distillation is not an Appropriate technique.

b. True...As there will be No Bond Formation between Water & p-dichlorobenzene, also there's a huge difference in boiling point between Water (i.e. 100 oC) & p-dichlorobenzene (i.e. 174 oC) so Steam Distillation can be used.

c. False...Not always, In case of Minimum Boiling Azeotropes it is less than 100 oC but in case of Maximum boiling azeotropes it is more than 100 oC

2.

a. Fractional Distillation

b. Steam Distillation

c. Simple Distillation