Return to Contents Chapter 4: Alcohols and Alkyl Halides Ch 4 contents


Functional group suffix = -ol
Functional group prefix = hydroxy-

Review alcohol nomenclature ?

Primary, secondary or tertiary ? Alcohols are described as being primary (1o), secondary (2o) or tertiary (3o) depending on how many alkyl substiutents are attached to the carbon that carries the -OH unit.

Check the designations of primary, secondary and tertiary by counting the number of C atoms attached to the C with the -OH attached.

Physical Properties:

Structure: Reactivity:
electrostatic potential of methanol The image shows the electrostatic potential for methanol. 
The more red an area is, the higher the electron density and the more blue an area is, the lower the electron density. 
  • The alcohol O atom are a region of high electron density (red) due to the lone pairs.

  • (red
  • Alcohol oxygen atoms are Lewis bases.
  • So alcohols can react as either bases or nucleophiles at the oxygen.
  • There is low electron density (blue) on H atom of the -OH group alcohol, i.e. H+ character.
  • So alcohols are acidic (pKa ~ 16).
  • Removal of the proton generates the alkoxide.
  • The -OH group is a poor leaving group and needs to be converted to a better leaving group before substitution can occur.


Reaction of Na with ROH or H2O

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organic chemistry © Dr. Ian Hunt, Department of Chemistry University of Calgary