Q 2 organic expiriments

• preparation of ethene

  • Glass wool holds ethanol in place
  • Alluminium Oxide ( Al2O3) placed halfway along boiling tube and heated
  • Allow bubbles to escape for a short time before using a boiling tube to collect gas
• Saftey steps for preparation of ethene

  • Dont heat ethanol directly ( glass wool is flammable)
  • remove delivery tube from water before removing heat as this prevents suck-back
• Physical properties of ethene

  • colourless gas with sweetish smell
  • burns with yellow luminous flame
• test for unsaturation

  • decolourises Bromine water ( red to colourless )
  • decolouises acidified potassium permanganate ( purple to colourless )
• steps in preparing ethyne

  • water slowly added to calcium carbide ( CaC2 )
  • effervescence observed
  • calcium hydroxide formed ( Ca( OH)2 )
  • Exothermic reaction
  • acidified copper sulphate solution removes impurities such as hydrogen sulfide, phosphine and ammonia
• Physical properties of ethyne

  • burns with smoky luminous flame
  • soot formed from unburnt carbon
• equation of combustion for ethyne

  2C2H2 + O2 --> 4CO2 +H2O
• equation of combustion for ethene

  C2H4 + O2 --> 2CO2 + H2O