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CBSE Guess > Papers > Important Questions > Class X > 2014 > Chemistry > Chemistry By Mrs. Kritika Bhola

CHEMISTRY CBSE CLASS X

Ethanol / Ethyl Alcohol (C2H5OH )

Physical  properties :-

  1. Colourless liquid having pleasant smell and burning taste .
  2. Volatile liquid having low boiling point .
  3. Lighter than water so it is soluble. Solubility of ethanol in water is due ot the presence of hydroxyl group in it.
  4. Does not contain any hydrogen ions – neutral compound.
  5. 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

    1. Since it burns with a clear flame giving lot of heat, it is used as a fuel.
    2. Used as an additive in petrol. It does not produce any poisonous gas like carbon monoxide .
    3. 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 + C2H5 OH → CH3COOC2H5 + H2O

    • 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 : kritikabhola@yahoo.co.in