One of the most important skills to acquire in your study of organic chemistry is to be able to
What does change?
The types of bonds at the carbon bearing OH
Examples:
to predict the product arising from a particular reactant OR
to predict the reactant that would give a particular product.
In order to be able to do this for oxidation reactions involving alcohols, it is critical to recognise that these reactions do not changeto predict the reactant that would give a particular product.
the arrangement of carbons (carbon skeleton)
the position of the carbon-oxygen bond
This means that the product and the reactant of an oxidation reaction havethe position of the carbon-oxygen bond
the same number and arrangement of carbons
oxygen bonded to the same carbon
oxygen bonded to the same carbon
What does change?
The types of bonds at the carbon bearing OH
The number of bonds from that carbon to oxygen increases
The number of bonds from that carbon to hydrogen decreases.
The number of bonds from that carbon to hydrogen decreases.
Examples:
 at C bearing O 1 bond to O 1 bond to H | H2CrO4 (K2Cr2O7/H+)  |  at C bearing O 2 bonds to O 0 bonds to H |
 at C bearing O 1 bond to O 2 bonds to H | limited H2CrO4 (K2Cr2O7/H+) |  at C bearing O 2 bonds to O 1 bond to H |
| excess H2CrO4 (K2Cr2O7/H+) |  at C bearing O 3 bonds to O 0 bonds to H |