CBSE Chemistry Subject Notes

CBSE Guess > eBooks > Class X > Carbon and Its Compounds By Mrs. Kritika Bhola

Chemistry

Carbon and Its Compounds

ETHANOL / ETHYL ALCOHOL ( C₂H₅OH )

Physical  properties  :-

• Colourless liquid having pleasant smell and burning taste .
• Volatile liquid having low boiling point .
• Lighter than water so it is soluble. Solubility of ethanol in water is due ot the presence of hydroxyl group in it.
• Does not contain any hydrogen ions – neutral compound.
• No effect on litmus paper.

Chemical properties  :-

1. Combustion :-  It is highly inflammable liquid and catches fire easily and starts burning in air with a blue flame to form CO₂ and water vapour and releases lot of heat and light.
   C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O + heat + light

• Since it burns with a clear flame giving lot of heat, it is used as a fuel.
• Used as an additive in petrol. It does not produce any poisonous gas like carbon monoxide .
• Produced on large scale from sugarcane crop. ( after crystallization of sugar from concentrated sugar cane juice , a thick, dark brown liquid called molasses is left behind. Ethanol is produced by fermentation of the cane sugar present in molasses)

2. Oxidation  :-  It means controlled combustion. When ethanol is heated with alkaline potassium permanganate solution , it gets oxidized to ethanoic  acid.
   CH₃CH₂OH + 2O → CH₃COOH  +  H₂O
   Ethanoic acid  is formed by the oxidation of ethanol by using a strong oxidizing agent.
   1. Oxidation of ethanol to ethanoic acid can also be done by using acidified potassium dichromate as the oxidizing agent ( in place of alkaline potassium permanganate) .
3. Reaction with sodium metal :- Ethanol reacts with sodium to form sodium ethoxide and hydrogen gas :
   2C₂H₅OH + 2Na ? 2 C₂H₅ONa + H₂
4. Dehydration :- It means removal of water molecule from it.
   When ethanol is heated with excess of conc. H₂SO₄ ( dehydrating agent)it gets dehydrated to form ethene.
   CH₃- CHOH ?CH₂= CH₂ + H₂O
5. Reaction with Ethanoic acid :- Ethanol reacts with ethanoic acid on warming in the presence of a few drops of conc. H₂SO₄ to form a sweet smelling ester , ethyl ethanoate .
   CH₃COOH + C₂H₅OH ? CH₃COOC₂H₅ + H₂O
   1. The reaction in which a carboxylic acid combines with an alcohol to form an ester is called esterification. It takes place in the presence of a catalyst H₂SO₄ .

USES OF ETHANOL

1. Manufacture of paints, varnishes, medicines, perfumes, dyes, soaps and synthetic rubber.
2. Used as a solvent.
3. Used as a fuel.
4. Used in alcoholic drinks
5. Used as an antiseptic to sterilize wounds.

Submitted By Mrs. Kritika Bhola
Email Id : [email protected]