We must have heard about the different organic compounds which have some functional groups. The presence of functional group in the molecule imparts characteristic physical and chemical properties to molecule. Some common example of functional groups are –COOH, -OH, -CHO, >C=O etc. The carboxyl group that is –COOH forms carboxylic acid with general formula RCOOH. They are organic compounds with pungent smell and acidic nature due to presence of –COOH group in the molecule. First member of carboxylic acid is formic acid which is formulated as HCOOH. Since there is only one carbon atom therefore the IUPAC name of molecule would be methanoic acid.
Next member of this series is acetic acid or ethanoic acid. The chemical formula of molecule is CH3COOH. Carboxylic acids are better known with their common names. For example; methanoic acid is found in red ants (Formica) so named as Formic acid. Similarly ethanoic acid can be extracted from acetum (a fruit) therefore named as acetic acid. Acetic acid is better known for its sour and pungent smell of vinegar in which acetic acid is present. Vinegar is 4 – 8% solution of acetic acid in water and mainly used as household essential for cooking and to unclog sinks. IUPAC name of acetic acid is ethanoic acid or methane carboxylic acid. The molecular formula is CH3COOH. It is a colorless liquid with a strong and distinct pungent and sour smell. The structural formula of molecule is shown below.
The hydrogen atom of –COOH
group is acidic in nature and can be release in the form of hydrogen ion. The acetic acid molecule converts into acetate ion with chemical formula CH3COO-. The acetate ion is stabilized due to delocalization of negative charge over two electronegative oxygen atoms. So acetic acid is acidic in nature due to;
- Formation of acetate ion
- Stabilization of acetate ion due to resonance
It is weak carboxylic acid which cannot ionize completely in its solution so un-ionized molecules remain in equilibrium with acetate ions and hydrogen ions. Due to weak nature, acetic acid has many applications even in chemical industry and organic chemistry. It forms one of the most common buffer solutions with sodium acetate which exhibits resistance against change in pH for different reaction systems.
Acetic acid is a monocarboxylic acid as it has one –COOH group. It is one of the most common organic reagents with various applications. It has different industrial applications and also involves in the preparation of different chemical compounds.
is one of the most common solvent for different industrial processes. It involves in manufacturing of various dye stuffs and perfumes. Acetic acid is used in manufacturing of rayon fibre, synthetic fibres and textiles. The acidic medium in the manufacturing of inks and dyes can be maintained with the help of acetic acid. It is also involved in manufacturing of rubber and plastic industries. It is also used in manufacturing of pesticides, wood glues and soft drinks bottles. For testing blood in clinical laboratory acetic acid is used. Acetic acid is also for the treatment of outer ear infections from the growth of fungus and bacteria. It is also used in film industry and food additives. It is a common food preservative and also used in medical industries, for household cleaning, health and hygiene and food flavoring.
Acetic acid is mainly used in the form of vinegar which is a dilute solution of it. Vinegar is widely used for cooking, cleaning, laundry and many other household uses. In the volcano science experiment, lava is produced by reaction of vinegar with baking soda and colour is due to red food color. Today different flavor of vinegar are available in market like balsamic vinegar, apple cider vinegar, red and white wine vinegar. There are many organic compounds and polymers like vinyl acetate, acetic anhydride, ester etc. Acetic acid is used for the production of vinyl acetate which is monomer for many polymers widely used for manufacturing of paints, adhesives, packaging, and more. Acetic acid
is also used for the production of acetic anhydride which is main ingredient for the production of cellulose acetate. Cellulose acetate is used to make a cellulose acetate film, used in photography. You must be familiar with the fruity smell of esters in chocolates. Esters are mainly prepared from the reaction of acetic acid with alcohols. They are widely involved in the preparation of other organic compounds also such as ethyl acetate and isobutyl acetate. Esters are also used in manufacturing of inks, paints, and coatings.
Acetic acid is main ingredient in many medicines and also used for the treatment of different infections such as outer ear infection. Use of acetic acid prevents the growth of bacteria and fungus. It helps to reduce the pain and swelling in the ear. In our ear, wetness promotes the growth of bacteria and fungus. Mixture of acetic acid with glycerin or alcohol prevents this growth and cures the infection. During this medication, avoid touching the ear with the dropper, have another person insert the drops. To avoid the risk of dizziness, hold the container in hand for a few minutes to make it warm.
In food industry, acetic acid is mainly used as vinegar which is diluted acetic acid. Vinegar is used in commercial pickling operations, in pickled food, condiments such as ketchup, mayonnaise and mustard. It is also used for salad dressing and marinades. It provides flavour to fish and chips, spinach, and cabbage. Vinegar can be used to sour milk to create a substitute for buttermilk. Reaction of vinegar with alkaline ingredients like baking soda produces a gas which helps to make baked goods rise.
Acetic acid is well known for its acidic nature.
The weak acidic nature makes it important in different industries mainly food industry. The dilute solution of acetic acid is known as vinegar which is mainly used as preservative in different food items as at low pH, the activity of bacteria reduces and preserve it. Vinegar is also used for its sour taste and as an aroma component.