Q. In general what are the products and reagents of fermentation?

In fermentation glucose sugar is degraded into pyruvic acid each glucose molecule forms two pyruvic acid molecules, in this process two molecules of ATP are produced.

According to the type of fermentation, pyruvic acid can produce carbon dioxide and ethanol (in alcoholic fermentation) or lactic acid in lactic fermentation. There are other varieties of fermentation in which pyruvic acid can generate acetic acid acetic fermentation, propionic acid, isopropanol (an alcohol too), and so on. The kind of fermentation depends on the species of the involved organisms.