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Ethanoic Acid – Structure, Properties, Uses, Sample Questions

  • Last Updated : 19 Oct, 2021

Carbon is a nonmetal that is required for life to exist. The name comes from the Latin word ‘carbo,’ which meaning ‘coal.’ This is due to the fact that it is coal’s most significant component. From fossil fuels to complex molecules, carbon is the most abundant chemical in most organic materials. Carbon dioxide makes up only 0.03 % of the atmosphere, and the Earth’s crust contains only 0.02 % carbon in the form of minerals. Despite the fact that carbon is present in very little amounts in nature, its importance appears to be enormous: carbon compounds are found in fossil fuels, polymers, soaps, detergents, and the bulk of the pharmaceuticals we use.

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 (which is a one-carbon carboxylic acid). 

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Although ethanoic acid is the proper and technically legitimate IUPAC term for this acid, its popular name, acetic acid, is frequently used as its IUPAC designation. Vinegar is a popular home product made from a solution of 5-8 % Ethanoic Acid in water. It is commonly used in kitchens. Ethanoic acid freezes throughout the winter and takes on the appearance of a glacier; as a result, it is also known as glacial acetic acid and is a popular laboratory chemical.

Structure of Ethanoic Acid

Ethanoic acid has the chemical formula 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).

Structure of Ethanoic Acid

After Methanoic acid, Ethanoic acid has the second simplest carboxylic acid structure. The carboxylic acid functional group (–COOH) is linked to a methyl (–CH3) group. Some suggest that a connection between an acetyl group (–CH3CO) and a hydroxyl group (–OH) is responsible for its structure. Hybridization with sp2 is seen. Because of the intermolecular hydrogen bonding that occurs between two molecules of ethanoic acid, it usually resides as a dimer in the liquid and vapour states. The electron cloud of the less electronegative hydrogen atom attracts the more electronegative oxygen atom of the carboxylic acid group, establishing a hydrogen bond.

Physical Properties of Ethanoic Acid

  • Pure Ethanoic Acid is a colourless, transparent liquid with a distinct odour.
  • The blaze point of Ethanoic Acid is 39°C.
  • The thickness of Ethanoic Acid is 1.05 g/cm3.
  • The limit of Ethanoic Acid is 118°C and its softening point is 16°C.
  • Ethanoic Acid has one hydrogen bond benefactor and two hydrogen bond acceptor iotas.
  • The dissolvability of unadulterated Ethanoic Acid in water is >100 mg/mL at 25°C. It infers that it is profoundly dissolvable in water in all extents.
  • 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, CH3)2CO, glycerol and ethanol.
  • The fume strain of Ethanoic Acid is 15.7 mm Hg at 25°C.
  • The LogP of Ethanoic Acid is – 0.17.
  • Ethanoic Acid is by and large stable at ordinary lab stockpiling temperature and different conditions.
  • The thickness of Ethanoic Acid is 1.056 mPa-s at 25°C.
  • The surface pressure of Ethanoic Acid is 27.10 mN/m at 25°C.
  • The hotness of ignition of Ethanoic Acid is 874.2 kJ/mol.
  • The hotness of vaporization of Ethanoic Acid is 23.36 at 25°C.
  • The pH of 1.0 Molar arrangement of Ethanoic Acid is 2.4.
  • The pKa (separation steady) of Ethanoic Acid is 4.76 at 25°C.

Chemical Properties of Ethanoic Acid

  • 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) as shown 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:


This salt (Sodium ethanoate) has a variety of industrial applications, including 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

Method of Preparation of Ethanoic Acid: Carbonylation of methanol is the most frequent technique of obtaining Ethanoic acid. Methanol is reacted with carbon monoxide in the presence of metal carbonyl as a catalyst to produce acetic acid.

Uses of Ethanoic Acid

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

Sample Questions

Question 1:  What is the 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.

Question 2: What happens when ethanoic acid reacts 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.

Question 3: What are the smell of ethanol and ethanoic acid?


Ethanol is a flammable, volatile, colourless liquid with a pleasant odour, whereas ethanoic acid is a colourless liquid with a strong vinegar-like odour.

Question 4: What are the 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.

Question 5: What is the 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.

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