PRACTICE QUESTIONS

• A student plans to investigate the yield of propanoic acid when a sample of propan-1-ol is oxidised. The figure shows the apparatus that the student plans to use for the experiment.

  Give two reasons why the apparatus shown in above figure is not safe.

  Flask is not clamped

  Sealed system/ bung in condenser
• A student plans to investigate the yield of propanoic acid when a sample of propan-1-ol is oxidised. The figure shows the apparatus that the student plans to use for the experiment.

  Give one additional reagent that is needed to form any propanoic acid.

  Dilute sulfuric acid
• A student plans to investigate the yield of propanoic acid when a sample of propan-1-ol is oxidised. The figure shows the apparatus that the student plans to use for the experiment.

  State two more mistakes in the way the apparatus is set up in the above figure.

  Direction of water flow through condenser

  Thermometer not needed
• A student plans to investigate the yield of propanoic acid when a sample of propan-1-ol is oxidised. The figure shows the apparatus that the student plans to use for the experiment.

  State the purpose of the small glass beads in the flask in above figure.

  Prevent bumping and large bubbles
• State a simple chemical test that distinguishes the propanoic acid from the propan-1-ol.

  Give one observation for the test of each substance.

  Acidified potassium dichromate

  PROPANOIC ACID: orange

  PROPAN-1-OL: turns green
• What compound is produced when 1-phenylethanol reacts with acidified potassium dichromate (VI).

  C6H5COCH3
• Describe a test-tube reaction, on the product, to show that the cyclohexanol had been dehydrated. State your observations.

  Bromine water

  Will turn from orange to colourless
• Suggest why sodium carbonate was used to wash the distillate.

  Would neutralise H3PO4
• Explain why it is important to open the tap of the separating funnel periodically.

  Release pressure
• Give a property of anhydrous calcium chloride, other than its ability to absorb water, that makes it suitable as a drying agent in this preparation.

  Does not dissolve in cyclohexene
• Which statement is correct about both 2-methylbutan-1-ol and 2-methylbutan-2-ol.

  They can be formed by alkaline hydrolysis of esters
• Which alcohol can be oxidised by acidified potassium dichromate (VI) but cannot be dehydrated by heating with concentrated sulfuric acid.

  2,2-dimethylpropan-1-ol
• Describe how the students would use this apparatus to collect a sample of ethanol.

  Turn on water

  Heat flask with Bunsen burner

  Produces ethanol and water vapours

  Vapours pass up A

  Water and ethanol are separated in A

  Water condenses back into flask in A

  Observe temperature at B (keep at/ below boiling point of ethanol)

  Only ethanol vapours pass into condenser

  Use condenser at C to cool vapours and condense ethanol back into a liquid