Carbon and Its Compounds

HYDROCARBONS


A compound made up of hydrogen and carbon only . Natural source is petroleum.
Two types--  Saturated ; unsaturated

  1. Saturated  Hydrocarbons  (Alkanes)-

 Carbon atoms are connected with single covalent bonds and end with ‘ane’. They are unreactive.
The general formula is CnH2n+2

  1. Unsaturated  Hydrocarbons ( Alkenes  and Alkynes) -

 Carbon atoms are connected by a ‘double bond’ or a ‘triple bond’ .These are obtained mostly from petroleum by a process called cracking.

  1. Alkenes ---  CnH2n

Alkenes contain a double bond between two carbon atoms which is formed by sharing of two electron pairs. Simplest alkene is Ethene.

  1. Alkynes --- CnH2n-2

Alkynes contain a triple bond between two carbon atoms which is formed by sharing of three electron pairs. Simplest Alkyne is Ethyne whose common name is Acetylene.

Alkyl  Groups ---- CnH2n+1

The group formed by the removal of one hydrogen atom from an alkane molecule .
Methyl group (CH3- ) is formed by the removal of one  H  atom from Methane  (CH4) , etc.

Cyclic  Hydrocarbons

Hydrocarbons in which the carbon atoms are arranged in the form of a ring. They may be saturated or unsaturated.

  1. A saturated cyclic hydrocarbon is ‘cyclohexane’ –  C6H12

Electron dot structure is obtained by putting two electron dots in place of every single bond in its structural formula.

Cyclopropane - C3H6

Cyclobutane – C4H8

Cyclopentane - C5H10

General formula of cycloalkanes  is CnH2n

  1. An unsaturated cyclic hydrocarbon is ‘ benzene’ ( aromatic  compounds ) whose electron dot structure is  --  2 electrons in place of every single bond and 4 electrons in place of every double bond in its structural formula.

Single  bond  --  2 shared electrons
Double bond  --  4 shared electrons

Naming Hydrocarbons ---

1 carbon atom Meth
2 Eth
3 Prop
4 But
5 Pent
6 Hex
7 Hept
8 Oct
9 Non
10 Dec

 

Single  Bond

ane

Double Bond

ene

Triple  Bond

yne

 Isomers :- The organic compounds having the same molecular formula but different structures.

  • Normal butane has a straight line structure whereas iso-butane structure has a branched chain structure.
  • Isomerism is possible only with hydrocarbons having 4 or more carbon atoms ie. Isomerim is not possible in methane, ethane and propane.
  • 1st isomer  is called n- pentane (normal)
  • 2nd isomer is called isopentane
  • 3rd isomer is called neopentane

 

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

Privious Next