Carbon and Its Compounds

Substitution reaction The reaction which involves direct replacement of an atom or group of atoms in an original molecule is called substitution reaction. Only saturated hydrocarbons perform substitution reactions.

CH₄      +        Cl₂   CH₃Cl      +        HCl

ETHANOL (CH₃CH₂OH or C₂H₅OH)

Physical properties

1. It is liquid at room temperature.
   
2. It is colourless and has distinct smell and burning taste.
   
3. It is soluble in water in all proportions.
   

Chemical properties

1. It reacts with sodium to form sodium ethoxide and hydrogen gas.
   

2CH₃CH₂OH + 2Na 2CH₃CH₂ONa + H₂

2. It reacts with hot concentrated H2SO4 to give ethene.
   

CH₃CH₂OH CH₂=CH₂ + H₂O

USES

1. It is used in all alcoholic drinks like wine, beer, etc.
   
2. In the form of rectified spirit (95% alcohol + 5% water), it is used as an antiseptic for wounds.
   
3. It is used in medicines like tincture iodine, cough syrups, tonics etc because it is a good solvent.
   
4. In cold countries it is used as antifreeze in automobiles.