Final answer:
In alcohol reactions, dehydration typically involves C-O bond cleavage, while oxidation usually involves changes in bonding but not necessarily direct O-H bond cleavage.
Step-by-step explanation:
Chemical reactions in alcohols primarily occur at the functional group involving the hydroxyl (-OH) group. When considering the two major types of reactions of alcohols, dehydration and oxidation, different bonds are involved.
In dehydration reactions, the bond cleavage typically involves the C-O bond where the hydroxyl group is removed as water. However, in oxidation reactions, the molecules undergo a change in the bonding around the carbon to which the hydroxyl group is attached, but do not always involve the direct breaking of the O-H bond itself.
For example, oxidation of a primary alcohol leads to the formation of an aldehyde, and further oxidation can yield a carboxylic acid. Secondary alcohols upon oxidation typically form ketones. Whether the C-O or O-H bond is cleaved during an alcohol reaction depends on the type of reaction and the structure of the alcohol molecule in question.