Carbon and Its Compounds Ethanol and Ethanoic Acid

These notes are based on the chapter Carbon and its Compounds from class 10 science of NCERT book and CBSE syllabus.

Ethanol (C₂H₅OH)

• Ethanol is commonly known as alcohol and spirit.
• General name of ethanol is ethyl alcohol.
• Ethanol is the main constituent of all alcoholic drinks
• Ethanol is soluble in water
• Ethanol is a very good solvent
• Ethanol is used in manufacturing of medicines, such as tincture iodine, cough syrup, etc.
• Taking even small quantity of pure ethanol may prove lethal
• Taking dilute ethyl alcohol can cause drunkenness

Chemical Properties of Ethanol

Reaction of ethanol with sodium metal:

When ethanol reacts with sodium, it gives sodium ethoxide and hydrogen gas.

2CH₃CH₂OH + 2Na ⇨ 2CH₃CH₂ONa + H₂

Oxidation of ethanol: Ethanol gives ethanoic acid on oxidation.

CH₃CH₂OH + (Alkaline KMnO₄/Acidified K₂Cr₂O₇) ⇨ CH₃COOH

Dehydration of ethanol: Ethanol gives ethene and water when it is heated with concentrated sulphuric acid.

CH₃CH₂OH + Conc. H₂SO₄ ⇨ CH₂=CH₂ + H₂O

Ethanoic Acid (CH₃COOH)

Structural formula of ethanoic acid is as follows:

• General name of ethanoic acid is acetic acid.
• Melting point of ethanoic acid is 290K.
• Ethanoic acid freezes in winter and hence it is also known as glacial acetic acid.
• Ethanoic acid is a colorless liquid.
• 5% to 8% solution of acetic acid in water is known as vinegar.
• Vinegar is used as preservative in pickles.
• Carboxylic acids are weak acid compared to mineral acids.

Chemical Properties of Ethanoic Acid

Reaction of ethanoic acid with base: Ethanoic acid gives sodium acetate when it reacts with sodium hydroxide.

CH₃COOH + NaOH ⇨ CH₃COONa + H₂O

Esterificaiton of ethanoic acid: Ethanoic acid gives ethyl acetate when it reacts with ethanol in presence of conc. sulphuric acid. This reaction is called esterification reaction.

CH₃COOH + C₂H₅OH ⇨ CH₃COOC₂H₅ + H₂O

The IUPAC name of Ethyl acetate is Ethyl Ethanoate. Ethyl acetate is also known as ester. Ester is a sweet smelling compound. It is used in making perfumes and as a flavouring agent. When ethyl ethanoate reacts with a base or acid, it gives back ethanol and ethanoic acid.

CH₃COOC₂H₅ + NaOH ⇨ CH₃COOH + C₂H₅OH

Hydrolysis of ester (Ethyl ethanoate): Ethyl ethanoate gives parent alcohol and sodium ethanoate when heated with sodium hydroxide solution.

CH₃COOC₂H₅ + NaOH ⇨ CH₃COONa + C₂H₅OH

Saponification: Ester of higher fatty acids gives sodium salt of higher fatty acid; when heated with glycerol and sodium hydroxide. Sodium salts of higher fatty acid are known as soaps. This reaction is called saponification (soap making).

Reaction of ethanoic acid with sodium carbonate and sodium bicarbonate:

Ethanoic acid gives sodium acetate, water and carbon dioxide when reacts with sodium carbonate or sodium bicarbonate (sodium hydrogen carbonate).

2CH₃COOH + Na₂CO₃ ⇨ 2CH₃COONa + CO₂ + H₂O

CH₃COOH + NaHCO₃ ⇨ CH₃COONa + CO₂ + H₂O