Fermentation is good thing. Wines are due to fermentation of sugar in fruit juices to ethanol. Prolonged fermentation on the other hand by a certain species of bacterium leads to a chemical change of ethanol to ethanoic acid which also known as acetic acid. Home vinegar is five percent by mass acetic acid.
Dilute acetic acid in the form of vinegar has many home and culinary purposes. But the industrial acetic acid is popularly incorporated in the manufacture of vinyl acetate monomer (VAM). The production of this substance draws a third of the total consumption of the acid. VAM ends up in the market in the form of adhesives, paper, paints, and textiles.
Terephthalic acid is another substance Acidaburn derived from acetic acid. The high demand of polyester fibers has been the reason for the demand on this compound. Of course, it is used in fabrics for clothes, garments, bed sheets, curtains, and draperies. This industry takes about twenty percent of the total consumption of acetic acid.
Acetate esters draw about fifteen percent of the consumption of acetic acid. These compounds, that are products of reactions between the organic acid and an alcohol, are important in the production of solvents for paints and inks.
The acid under discussion is known for some medical purposes. It is a mild anti-bacterial agent. During white blood cell counts, it is used to destroy red blood cells. The mild acidic properties treat stings from box jellyfish. It also slows fungal growth. The popular vinegar is a food additive and preservative.
Acetic acid is one of the simplest carboxylic acids with a chemical formula CH3COOH and it freezes at 16.7 degrees Celsius. In its pure form, acetic acid is a white crystalline solid. This organic acid is one of the weakest acids by nature. In aqueous solutions, it only partially dissociates into acetate and hydrogen ions. However, weak as it is, this acid can be very corrosive and irritating at high concentrations.
What gives it an acidic nature is the hydrogen in the carboxylic group, COOH. In solutions with water, hydrogen is given as H+ ion. The other ion is the acetate ion, CH3COO-. The organic acid is a hydrophilic substance, which explains why it dissolves readily in water. This solubility accounts for its vast industrial use.
Like any other acids, inorganic or not, it reacts with metals to yield hydrogen gas and acetate salts. Metals like iron, magnesium and zinc may corrode in contact with acetic acid. For instance magnesium reacts with the acid to form magnesium acetate and hydrogen gas. Although reactions like this one have industrial purposes, it restricts the storage only to certain materials and the acid cannot be safely placed for storage and transportation in certain metals. It should be transported using aluminum tanks or containers, as aluminum forms a thin layer of aluminum oxide when exposed to the oxygen in the air. This film of aluminum oxide serves to resist corrosion in the presence of the acid.
A popular grade school science experiment is the reaction of the acid to baking soda (chemically known as sodium bicarbonate). This reaction yields water, carbon dioxide (which fizzes and bubbles up) and sodium acetate, which is metal acetate. Metal acetates can be actually formed in the same fashion. The reaction of the acid with a metallic base yields an acetate compound.