Practical questions on preparation of an ester and aspirin

Why is the distillate collected in a flask surrounded by ice?

Prevents the organic liquid from evaporating or decomposing

How could you obtain ethanal from the mixture collected at the end of the experiment?

To obtain ethanal from the mixture, you would oxidize the ethanol (present in the mixture) using a mild oxidizing agent like potassium dichromate in dilute sulfuric acid, and then distill off the ethanal

Why is the mixture poured onto crushed ice?

The mixture is poured onto crushed ice to cool the reaction and help precipitate the aspirin

Why is suction filtration used over gravity filtration?

Suction filtration is preferred over gravity filtration in this case because it is faster, more efficient, and helps to retain the solid aspirin better, ensuring higher yield and purity

How is the impure product recrystallised?

To recrystallize impure aspirin, dissolve it in a hot solvent, filter off any insoluble impurities, allow the solution to cool, and then collect the purified aspirin crystals by suction filtration, washing them with cold solvent and allowing them to dry

Why is ethanoic anhydride preferred in industry over ethanoyl chloride?

• Less corrosive

• Less vulnerable to hydrolysis

• Less hazardous as less volatile

• Cheaper

• Does not produce toxic fumes like HCl