alcohols

• What is the functional group of an alcohol?

  -OH (hydroxile group)
• What intermolecular forces are found in alcohols?

  1* London forces

  2* Hydrogen bonding as a result of the electronegativity from the OH group
• How does the bpt of an alcohol compare to that of its corresponding alkane?

  Alcohols will have higher bpt to their corresponding alkanes. This is due to its ability to form H-bonds that are stronger than London forces
• Are alcohols soluble in water? Explain (consider the effect of chain length)

  Short chain alcohols are soluble in water due to the presence of the OH group's ability to form hydrogen bond with the water.

  Long chain alcohols are insoluble in water due to non-polar C-H bonds that are favoured
• Draw a primary alcohol

  The -OH group is attached to the carbon bonded to one other carbon

  
• Draw a secondary alcohol

  The -OH group is attached to the carbon bonded to two other carbons

  
• Draw a tertiary alcohol

  The -OH group is attached to the carbon bonded to three other carbons

  
• What product is formed when you partially oxidise a primary alcohol? And state the conditions

  An aldehyde - dilute sulfuric acid, potassium dichromate (VI) in a distillation set up
• What product is formed when you completely oxidise a primary alcohol? And state the conditions

  A carboxylic acid - conc. sulfuric acid, potassium dichromate (VI) in a reflux set up
• What product is formed you completely oxidise a secondary alcohol? And state the conditions

  A ketone - conc. sulfuric acid, potassium dichromate (VI) in a reflux set up
• Write the equation for the partial oxidation of primary alcohol


  RCH2OH (l) + [O] →RCHO (g) + H2O (l)
• Write the equation for the complete oxidation of primary alcohol


  RCH2OH (l) + 2[O] → RCOOH (g) + H2O (l)
• Write the equation for the complete oxidation of secondary alcohol

  RCH(OH)CH3 (l) + [O] → RCOCH3 (g) + H2O (l)
• Explain why tertiary alcohols cannot be oxidised

  The OH group is attached to a carbon bonded to three other carbons so there is no H-bond that can be broken
• How do you identify the oxidation of an alcohol has taken place?

  A colour change of orange to green is observed. This is the dichromate (VI) being reduced to chromium (III) ions
• Explainwhat is meant by 'a dehydration reaction'

  A reaction where water is lost to form an organic compound
• What products are formed in a dehydration reaction of an alcohol?

  An alkene and water
• What conditions are required for the dehydration of an alcohol?

  Conc. sulfuric / phosphoric acid @ 170°C
• What are the products of the halide substitution reaction with alcohol?

  A haloalkane and water
• What form is the halide in a halide substitution reaction?

  A Hydrogen Halide eg HCl
• How is the hydrogen halide formed?

  Hydrogen halides can be formed by reacting a salt with acid:

  
  

  2NaBr + H₂SO₄ → 2HBr + Na₂SO₄
• What is the formula for acidified pottasium dichromate and what is the ionic formula?

  K2Cr2O7/H2SO4 and Cr2O72-/H+