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AlcoholsEdexcel A-Level Chemistry: Flashcards

What these 14 flashcards ask

  • How is an alcohol classified as primary, secondary or tertiary?
  • Write the equation for the complete combustion of ethanol.
  • Which reagent converts an alcohol to a chloroalkane?
  • Which reagents convert an alcohol to a bromoalkane?
  • Which reagents convert an alcohol to an iodoalkane?
  • What does a primary alcohol form when oxidised by acidified dichromate(VI)?
  • What does a secondary alcohol form on oxidation?
  • Why are tertiary alcohols not oxidised by acidified dichromate(VI)?
  • What colour change shows an alcohol has been oxidised by acidified dichromate(VI)?
  • How do you stop oxidation of ethanol at ethanal?
  • How do you oxidise a primary alcohol fully to a carboxylic acid?
  • What is the positive result for an aldehyde with Benedict's or Fehling's solution?
  • Which reagent dehydrates an alcohol to an alkene?
  • Why is a drying agent such as anhydrous sodium sulfate used?

Exam questions on Alcohols

  1. A technician is given four structural isomers of molecular formula C₄H₁₀O: butan-1-ol, butan-2-ol, 2-methylpropan-1-ol and 2-methylpropan-2-ol. She will warm each with acidified potassium dichromate(VI) solution and compare the results.
    Explain why 2-methylpropan-2-ol does not change the colour of acidified potassium dichromate(VI) solution when warmed.2 marks
  2. A chemist converts propan-1-ol into three different halogenoalkanes: 1-chloropropane, 1-bromopropane and 1-iodopropane. A different reagent or reagent mixture is needed for each halogen.
    Write two equations to show how potassium bromide and 50% concentrated sulfuric acid convert propan-1-ol into 1-bromopropane. The first equation shows the formation of the reactive halogenating species.2 marks
  3. A student carries out Core Practical 5 on the oxidation of ethanol using acidified potassium dichromate(VI). In one experiment she wants to collect ethanal; in a second experiment she wants to make ethanoic acid.
    Describe how she should carry out the experiment to collect ethanal, and explain why this method prevents further oxidation.3 marks
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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).