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Ethanoic Acid

Last Updated : 26 Sep, 2023
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Ethanoic Acid (CH3COOH) which is also known as Acetic Acid is the most generally available acid. Its common name is Vinegar. Vinegar is a popular home product made from a solution of 5-8 % Ethanoic Acid in water. Ethanoic Acid is commonly used in kitchens as a preservative for foods. Ethanoic acid is a weak acid and consuming it in mild concentration does not affect our health.

In this article, we will learn about What is Ethanoic Acid? Structure of Ethanoic Acid, Properties of Ethanoic Acid, Uses of Ethanoic Acid and others in detail.

What is Ethanoic Acid?

Ethanoic acid (also known as acetic acid) is a two-carbon acid that follows methanoic acid as the second member of the carboxylic acid family.

Ethanoic Acid (Acetic Acid) is a weak acid. It is a colourless liquid with the chemical formula CH3COOH it is denser than water. A 5-8% solution of Ethanoic Acid is called the Acetic Acid and it is used as food preservative and as pickling agent. As with all the acid it has a sour taste and it has a ph of less than 7.

Learn more about Acid, Base and Salts

Chemical Formula of Ethanoic Acid

Ethanoic acid is a member of carboxylic acid family. It is the second member of the carboxylic acid. The chemical formula for the Ethanoic Acid is, CH3COOH

Structure of Ethanoic Acid

Ethanoic Acid Structural Formula is CH3COOH, which may alternatively be written as CH3CO2H or C2H4O2 in its condensed form. It has a molecular mass of 60.05 g/mol (or molar mass). The structure of Ethanoic acid is added below:

Structure of Ethanoic Acid

Ethanoic acid is second member of Carboxyl Acid family after Methanoic Acid. In Ethanoic Acid the carboxylic acid functional group (–COOH) is linked to a methyl (–CH3) group.

Method of Preparation of Ethanoic Acid

Carbonylation of methanol is the most frequent technique for obtaining Ethanoic acid. Methanol is reacted with carbon monoxide in the presence of metal carbonyl as a catalyst to produce acetic acid. The reaction representing the same is added below,

C2H5OH (Ethanol) + 2[O] → CH3COOH (Ethanoic Acid) + H2O

Apart from this fermentation of carbohydrates also results in the formation of ethanoic acid.

Physical Properties of Ethanoic Acid

Basic physical properties of Ethanoic Acid are added in the table below,

Chemical formula CH3COOH
Molecular Weight/ Molar Mass 60.05 g/mol
Density 1.05 g/cm3
Melting Point 16°C
Boiling Point 118°C

Some other physcial properties of Ethanoic Acid are:

  • Pure Ethanoic Acid is a colourless, transparent liquid with a distinct odour.
  • Blaze point of Ethanoic Acid is 39°C.
  • Thickness of Ethanoic Acid is 1.05 g/cm3.
  • Ethanoic Acid has one hydrogen bond benefactor and two hydrogen bond acceptor ions.
  • Dissolvability of unadulterated Ethanoic Acid in water is >100 mg/mL at 25°C.
  • Ethanoic Acid is totally dissolvable in natural solvents, for example, carbon tetrachloride and carbon disulfide. It is miscible with natural solvents like ethyl ether, benzene, glycerol and ethanol.
  • Surface pressure of Ethanoic Acid is 27.10 mN/m at 25°C.
  • pH of 1.0 Molar arrangement of Ethanoic Acid is 2.4.
  • pKa (separation steady) of Ethanoic Acid is 4.76 at 25°C.

Chemical Properties of Ethanoic Acid

Ethanoic Acid is a very common chemical compound and it reacts with variety of other compounds to form various compound. The reactions of ethanoic acid are listed below:

  • Esterification Reaction
  • Reaction with Base
  • Reaction with Carbonates
  • Manufacturing of Soap

Let’s discuss these reactions in detail

Reactions of Ethanoic Acid

Some important chemical reaction of Ethanoic Acid are:

Esterification Reaction

When a carboxylic acid interacts with alcohol, it produces esters, which are a new family of chemical molecules. Esterification is the chemical process that results in the production of esters. When Ethanoic Acid (a carboxylic acid) combines with Ethanol (ethyl alcohol), it forms ethyl ethanoate (an ester). The reaction of Ethanoic Acid and Ethanol is added below,


This reaction produces a novel class of chemical compounds with a distinct fruity odour that makes them easily identifiable.

Esters are employed in the food business as synthetic flavouring agents and in the perfume industry for their pleasant scents. Apart from that, one of the most common uses of esters is in the manufacture of soaps. When esters react with any base (especially alkalis), a carboxylic acid salt is formed, which is the basic molecular structure of soap. The saponification reaction is the name for this process. This reaction is best carried out with higher molecular weight esters. The following is a broad explanation of the saponification reaction:


Reaction with Base

The acid ethanoic acid is a weak one. It interacts with a base to create one molecule of salt and one molecule of water, much like any other acid. Ethanoic acid reacts with Sodium Hydroxide (a base) to create sodium ethanoate and water, as shown below:


Sodium ethanoate has a variety of industrial applications, including the neutralisation of sulfuric acid (used to clean fibres) in the textile industry, as a preservative and mild seasoning and flavouring agent in the food industry, and as a buffering agent with Ethanoic acid (commonly known as the acetate buffer) to maintain the pH of a medium.

Reaction with Carbonates

When ethanol reacts with carbonates or hydrogen derivatives of carbonates (hydrogen carbonates, also known as bicarbonates), salt is formed as a by-product, along with carbon dioxide and water.

2CH3COOH + Na2CO3 → 2CH3COONa + CO2 + H2O

Manufacturing of Soap

Animal fats or vegetable oils (olive oils, castor oil, or palm oil) are heated with sodium hydroxide or potassium hydroxide to make the soap. To make soap, heat fat or vegetable oils with a strong sodium hydroxide solution until soap and glycerol are formed. Saponification reaction is the name given to the process of making soap. Glycerol is a valuable by-product of this process since it is used to make a variety of chemical compounds, explosives, and pharmaceuticals.

RCOOR’ (ester) + NaOH (base) → RCOO–Na+ (Soap) + R’OH (alcohol)

Uses of Ethanoic Acid

Ethanoic Acid found its importance in variety of things some of the common uses of Ethanoic Acid are,

  • It’s utilised as a solvent in a variety of processes that call for an aprotic solvent.
  • Vinegar, esters, and synthetic polymers are all made from it.
  • It is used in labs as a lysing agent for blood cells.
  • It is used to treat fungal infections.

Also, Check

FAQs on Ethanoic Acid

1. What is Chemical Name of Soap?

Sodium stearate is the sodium salt of stearic acid, a long-chain saturated fatty acid (C17H35COOH). The lengthy alkyl chain C17H35 and the ionic carboxylate group COO–Na+ are found in sodium stearate.

2. What is Reaction of Ethanoic Acid with Ethanol?

Ethanol combines with ethanoic acid to form a fruity-smelling molecule known as ethyl ethanoate, which is an ester. Esterification is the name given to this process.

3. What is Glacial Acetic Acid?

Glacial Acetic Acid is the other name of Ethanoic Acid and is called Glacial Acetic Acid, because it has a melting point of 16℃ and thus it freezes in colder temperature.

4. What are Uses of Ethanoic Acid?

The uses of Ethanoic Acid are:

  • It’s utilised as a solvent in a variety of processes that call for a protic solvent.
  • Vinegar, esters, and synthetic polymers are all made from it.
  • It is used in labs as a lysing agent for blood cells.
  • It is used to treat fungal infections.

5. What is Cleansing Action of Soap?

Oily or greasy compounds are not wettable by water. However, the soap anion’s hydrocarbon residue R (RCOO–) can do so.

When a filthy cloth is dipped into a soap solution owing to the deposition of dust, oil, or greasy substances, the hydrocarbon non-polar portion R (hydrophobic) of the RCOO– ion dissolves as polar impurities of oily or greasy dirt and encapsulates it in the micelle. The micelles that transport the oily or greasy particles are washed away when the fabric is cleaned with water.

6. What is Molar Mass of Ethanoic Acid?

Molar mass of Ethanoic Acid is 60 g/mol.

7. What is Ethanoic Acid Boiling Point?

Boiling point of Ethanoic Acid is 118℃

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