2020

• 1-chloropropane can also be produced by the reaction between propane and chlorine in the presence of ultraviolet light.

  State why ultraviolet light is needed for this reaction to occur.

  Provides energy to break covalent bond in Cl2
• Pent-1-ene is formed by the elimination of water from pentan-2-ol. State the reagent and condition for this reaction.

  Concentrated sulfuric/ phosphoric acid

  Hot
• Explain the differences between structural isomerism and stereoisomerism. Using C4H8 exhibit stereoisomerism and the three types of structural isomerism.

  STRUCTURAL ISOMERS

  • molecules with same molecular formula but different structure
  • different C chain (methylpropene and but-1-ene)
  • different position of functional group (but-2-ene and but-1-ene)
  • different functional group (methylpropene and but-1/2-ene)

  STEREOISOMERS

  • molecules with same structural formula but different arrangement of atoms in space
  • lack of rotation around C=C bond (E/Z but-2-ene)
• State why a plasticiser is added to PVC.

  Makes it more flexible
• Ethanedioic acid is formed by the oxidation of ethane-1,2-diol (HOCH2CH2OH). State suitable reagent(s) and a condition for this reaction.

  Acidified potassium (VI) dichromate

  Reflux
• Which statement is not correct about ozone?

  A It absorbs harmful ultraviolet radiation in the upper atmosphere.

  B It decomposes to form oxygen.

  C Its decomposition is catalysed by chlorine molecules.

  D Ozone holes are regions of the upper atmosphere where there is a reduced concentration of ozone

  C
• What is the IUPAC name of the major product of the reaction between 2-ethylbut-1-ene and hydrogen bromide?

  A 1-bromo-2-ethylbutane

  B 2-bromo-2-ethylbutane

  C 2-bromo-2-methylpentane

  D 3-bromo-3-methylpentane.

  D
• Which can be used to distinguish between these two compounds? (CH3)2CHCH2CHO and (CH3)3CCHO

  A Acidified potassium dichromate(VI)

  B Fingerprint region of infrared spectrum

  C Mr value in high resolution mass spectrometry

  D Tollens’ reagent

  B
• In which reaction does the inorganic reagent act initially as an electrophile?

  A bromoethane with ethanolic potassium hydroxide

  B chloroethane with aqueous sodium hydroxide

  C ethane with chlorine

  D ethene with concentrated sulfuric acid

  D
• Which statement is correct about the production and use of ethanol as a biofuel?

  A Biofuel ethanol is produced by the fermentation of glucose in the presence of yeast and air.

  B Biofuel ethanol is purified by fractional distillation.

  C No carbon dioxide is released when biofuel ethanol is burned.

  D Biofuel ethanol burns with a cleaner flame than ethanol made by hydration of ethene

  B