Fermentation in winemaking involves the contact of sugar and enzymes from crushed grapes, leading to the release of carbon dioxide. Zymase, an enzyme found in yeast, catalyzes this process under anaerobic conditions.

Methanol is produced through catalytic hydrogenation, is a colorless liquid with a boiling point of 337 K, and is highly poisonous. Ingestion, even in small quantities, can lead to blindness, and larger quantities can be fatal.

Commercial ethanol is obtained through fermentation, typically from sugars found in molasses, sugarcane, or fruits such as grapes. The sugars undergo conversion to glucose and fructose, followed by fermentation in the presence of yeast-derived enzyme zymase.

Oxidation of phenol with chromic acid produces benzoquinone. In the presence of air, phenols undergo slow oxidation, forming dark-colored mixtures containing quinones.

Heating phenol with zinc dust leads to the conversion of phenol to benzene. Zinc acts as a reducing agent, facilitating this transformation.