Distillation of alcohol. Image credit bbc.co,uk

Distillation of alcohol. Image credit bbc.co,uk

ZIMSEC O Level Combined Science Notes: Experiment: The distillation of ethanol

Aim: To concentrate alcohol using the distillation process

Materials: thermometer, clamp stands, rubber bungs, round bottomed flask, fractionating column. condenser with rubber tubing, watch-glass or tin lid, porcelain chips or clean dry sand

  1. Set up the apparatus as shown above, make sure that the round bottomed flask is not more than a third full to begin with, the thermometer is on the side opposite arm of the fractionating column and that cooling water is entering through the lower tube so that the condenser jacket is always full
  2. Remove any solid residue from the alcohol before adding it to the round bottomed flask
  3. Pour the solution into a round bottomed flask fitted with a fractionating column
  4. Add a few pieces of broken porcelain/clean sand to ensure even heating
  5. Try to ignite a few drops of the undistilled solution on a watch glass
  6. Heat the solution and collect the fractions coming off at 78°C,82°C,86°C,90°C and 94°C
  7. Ignite each farction on a watch glass to see if it will burn

Results and observations

  • The undistilled solution cannot be ignited on the watch glass
  • As the proportion of alcohol in a fraction increases it is easier to ignite
  • The concentration of alcohol is highest at 78°C
Temperature °CPercentage of Alcohol yieded

To access more topics go to the Combined Science Notes page.