Explain the following reactions with examples: Addition reaction, Substitution reaction, Combustion reaction.

Asked by Shubhi Gupta | 17th Nov, 2013, 10:56: PM

Expert Answer:

Substitution reaction:

 

  • The reaction in which one or more hydrogen atoms of a hydrocarbon are replaced by some other atoms is called a substitution reaction.
  • Substitutions reactions are a characteristic property of saturated hydrocarbons (Alkanes).
  • For example: Methane reacts with chlorine in the presence of sunlight to form     chloromethane and hydrogen chloride.

 

Where, R is an alkyl group.

 

Addition reaction:

  • The reaction which involves direct addition of an attacking agent, across the double or triple bonds are called addition reactions.
  • An unsaturated hydrocarbon combines with another substance to give a single product.
  • Addition reaction like the addition of hydrogen, chlorine or bromine are a characteristic property of unsaturated hydrocarbons.
  • This reaction occurs only in unsaturated compounds where there are double or triple bonds.

e.g.

 

 

Combustion Reaction:

  • Combustion or Burning is a chemical change in which combustible substances combine with oxygen to produce new products called oxides with the liberation of heat and light.
  • It is an exothermic reaction.

For example combustion of methane is given as under

CH+ 2O2 →  CO2 + 2H2O

Magnesium combines with oxygen to form white colour magnesium oxide with liberation of some amount of heat.

 

 

Answered by Hanisha Vyas | 18th Nov, 2013, 11:27: AM

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