Alcohols and their reactionsEdexcel International A Level Chemistry: Subtopic test

1. 1
   A technician is given a colourless liquid labelled as propan-2-ol, a solvent used in cleaning products, and wants to confirm that it is an alcohol and then convert it into a halogenoalkane.

   (a)

   How is propan-2-ol classified?

   [1 mark]

   • APrimary, because the OH group is on the end of the chain
   • BTertiary, because it contains three carbon atoms
   • CPrimary, because it has one OH group
   • DSecondary, because the carbon bonded to OH is attached to two other carbons

   (b)

   Which reagent gives steamy fumes of hydrogen chloride with all alcohols, and so is a qualitative test for the –OH group?

   [1 mark]

   • AConcentrated sulfuric acid
   • BPhosphorus(V) chloride
   • CAcidified potassium dichromate(VI)
   • DAqueous sodium hydroxide

   (c)

   The technician adds phosphorus(V) chloride to a sample of the liquid. State what is observed and write the equation for the reaction with propan-2-ol.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Butan-1-ol, C₄H₉OH, is being investigated as a possible biofuel. Relative atomic masses: C = 12.0, H = 1.0, O = 16.0.

   (a)

   Which equation shows the complete combustion of butan-1-ol?

   [1 mark]

   • AC₄H₉OH + 6O₂ → 4CO₂ + 5H₂O
   • BC₄H₉OH + 5O₂ → 4CO₂ + 5H₂O
   • CC₄H₉OH + 6O₂ → 4CO₂ + 4H₂O
   • DC₄H₉OH + 4O₂ → 4CO + 5H₂O

   (b)

   When butan-1-ol burns in a limited supply of oxygen, which products could form in addition to water?

   [1 mark]

   • ACarbon dioxide only
   • BHydrogen and carbon dioxide
   • CCarbon monoxide and carbon
   • DCarbon dioxide and hydrogen peroxide

   (c)

   Calculate the mass of carbon dioxide formed when 3.70 g of butan-1-ol burns completely in excess oxygen.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A chemist makes two different compounds from ethanol, one by a halogenation reaction and one by an elimination reaction, in separate experiments.

   (a)

   Ethanol is converted into bromoethane using potassium bromide and 50% concentrated sulfuric acid. State the conditions, show how the reactive reagent is formed, and write the equation for the reaction of ethanol with that reagent.

   [3 marks]

   (b)

   In the second experiment ethanol is heated with concentrated phosphoric acid. Name the organic product and the type of reaction, write the equation and state the role of the acid.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Butan-2-ol is a secondary alcohol used as a solvent. A research chemist uses it as the starting material to make a range of other compounds.

   (a)

   Describe the reactions of butan-2-ol with (i) phosphorus(V) chloride, (ii) potassium bromide and 50% concentrated sulfuric acid, and (iii) red phosphorus and iodine. Give the organic product of each and state one observation.

   [6 marks]

   (b)

   Butan-2-ol is heated with concentrated phosphoric acid. Predict the organic products and explain why a mixture of alkenes is formed.

   [6 marks]

   Total for question 4: 12 marks

End of questions