Acetic acid

ETHANOIC ACID (OR ACETIC ACID)

• Ethanoic acid (CH₃COOH) is a carboxylic acid, commonly called as acetic acid.
• It has a density of 1.05 g/cm³, making it slightly heavier than water.

WHAT IS ACETIC ACID?

• Acetic acid is the common name for the systematic name for ethanoic acid.
• It is mostly used as preservatives in pickles by adding 5-8% of acetic acid in water , making it turn into vinegar.

PHYSICAL PROPERTIES OF ETHANOIC ACID

• It is a colourless liquid having a sour taste and a smell of vinegar.
• The boiling point of ethanoic acid is (391K).
• When pure ethanoic acid is cooled, it freezes to form a colorless, ice-like solid which looks like a glacier. Due to this, pure ethanoic acid is called glacial ethanoic caid or glacial acetic acid.).
• Ethanoic acid is miscible with water in all proportions.

CHEMICAL PROPERTIES OF ETHANOIC ACID

ACTION ON LITMUS

• Ethanoic acid is acidic in nature. So, it turns blue litmus solution red.

REACTION WITH SODIUM CARBONATE

• Ethanoic acid reacts with carbonates and hydrogencarbonates to evolve carbon dioxide gas along with the formation of salt and water.
• Example:. Ethanoic acid reacts with sodium carbonate to form sodium ethanoate and carbon dioxide gas:

REACTION WITH SODIUM HYDROGENCARBONATE.

• Ethanoic acid reacts with sodium hydrocarbonate to evolve brisk effervescence of carbon dioxide gas:

REACTION WITH SODIUM HYDROXIDE

• Ethanoic acid reacts with bases (or alkalis) to form salts and water.
• For example, ethanoic acid reacts with sodium hydroxide to form a salt called sodium ethanoate and water:

REACTION WITH ALCOHOLS (FORMATION OF ESTERS)

• Ethanoic acid reacts with alcohols in the presence of a little of concentrated sulphuric acid to for, esters.
• For example, when ethanoic acid is warmed with ethanol in the presence of a few drops of concentrated sulphuric acid, a sweet smelling component called ethyl ethanoate is formed:

• Esters are usually volatile liquids having sweet smell or pleasant smell.
  • They are also said to have fruity smell.
  • Esters are used in making artificial perfumes (artificial scents).
  • Esters are also used as flavouring agents.

USES OF ETHANOIC ACID (OR ACETIC ACID)

• Dilute ethanoic acid (in the form of vinegar) is used as a food preservative in the preparation of pickles and sauces (like tomato sauce). As vinegar, it is also used as an appetizer for dressing food dishes.
• It is used for making cellulose acetate which is an important artificial fibre.
• It is used in the manufacture of acetone (propanone) and esters used in perfumes.
• It is used to coagulate rubber from latex.
• The reaction of esters with alkalis gives carboxylic acid salt and alcohol which is used in the making of soaps by the process called saponification reaction.

Ethyl ethonate      sodium hydroxide    ethanol     sodium ethanoate

• Used as an agent to lyse red blood cells before white blood cells are examined.
• Used as a solvent in the production of camphor, a scent and cooking ingredient.
• Used as a stop bath for photographic emulsion development.
• Farmers sometimes spray acetic acid on livestock silage to fight fungal and bacterial growth.