Question: Label each reaction as oxidation, reduction, or neither.

a.

b.

c.

d.

In general, oxidation involves the loss of electrons from a system or an atom, and reduction is the gain of electrons. In the case of organic chemistry, oxidation is the process where a carbon engages in bond formation with more electronegative elements (oxygen), and reduction is when it bonds with less electronegative elements (hydrogen).

a. Here, a decrease in the C-O bond is observed, and an increase in the C-H bond takes place. Thus, the given reaction is a reduction reaction.

Reduction reaction

b. As more bonds are formed with the electronegative oxygen atom, the reaction is an oxidation reaction.

Oxidation reaction

c. In this case too, oxidation occurs as more bonds are formed with the electronegative oxygen.

Oxidation reaction

d.The given reaction cannot be classified as oxidation or reduction. This is an example of a hydrogenation reaction.

Hydrogenation reaction