CHE005: LAS 4 Distillation Quiz

The principle of distillation is based on:

• Liquids have identical boiling points

• Different liquids boil at different temperatures

• Liquids solidify at different rates

• Vaporization occurs only in solids

Which phase changes occur during distillation?

• Melting and freezing

• Evaporation and condensation

• Sublimation and deposition

• Ionization and recrystallization

Distillation is a purifying technique because:

• It changes the chemical structure of a liquid

• It separates based on density differences

• It separates a volatile compound from a nonvolatile one

• It prevents liquid evaporation

In a mixture of a volatile compound A and nonvolatile compound B, which will distill?

• Both A and B

• Only B

• Only A

• Neither A nor B

A heat-sensitive liquid can be distilled without decomposition by:

• Using direct flame heating

• Employing a water bath or steam distillation

• Rapid boiling over a strong flame

• Cooling the mixture immediately

Which type of distillation separates liquids with close boiling points?

• Simple distillation

• Fractional distillation

• Vacuum distillation

• Steam distillation

Which type of distillation is suitable for substances that decompose at high temperatures?

• Simple distillation

• Fractional distillation

• Steam or vacuum distillation

• Zone distillation only

Air-sensitive compounds are distilled using:

• Steam distillation

• Short-path distillation

• Air-sensitive vacuum distillation with inert gas

• Simple distillation

The main purpose of heating under reflux is:

• To evaporate the solvent quickly

• To increase yield and prevent loss of reactants

• To avoid condensation during heating

• To lower boiling points of liquids

Why does heating under reflux take time?

• Organic reactions are generally fast

• Organic reactions are slow and need continuous heating to improve yield

• Condenser speed up reaction time

• Vapors escape without condensation