Alcohols

• Which alcohols can exist as structural isomers

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  • Alcohols with more than two carbon atoms can exist as structural isomers
• Polarity


  Alcohol molecules are polar and hydrogen bonds exist between the molecules
• Melting and boiling points

  Alcohols have relatively high melting points and boiling points, and low volatilities, compared with alkanes of a similar molecular mass because they have both hydrogen bonding and London forces where alkanes only have London forces
• Solubility


  Alcohols with a short carbon chain length are soluble in water, solubility decreases as the carbon chain length increases
• Primary alcohols


  The -OH group is bonded to a carbon which is bonded to one carbon atom
• Secondary alcohols


  The -OH group is bonded to a carbon which is bonded to two other carbon atoms
• Tertiary alcohols


  The -OH group is bonded to a carbon which is bonded to three other carbon atoms
• When a primary alcohol is oxidised


  It is converted to an aldehyde
• When a primary alcohol is further oxidised


  It is converted to a carboxylic acid
• When a secondary alcohol is oxidised


  It is converted to a ketone
• Ketones cannot be oxidised any further
• Elimination reaction


  Dehydrating agents, such as concentrated sulfuric acid, H2SO4, or phosphoric acid, H3PO4, can be used to remove water from alcohols
• Substitution reaction


  Alcohols react with hydrogen halides, such as hydrogen bromide, HBr, to produce haloalkanes
• The general formula for an alcohol is R-OH