Hydrocarbons Test - 2

Because hydrocarbons contain both C and H and hence Hydrogen is not a hydrocarbon. .

 saturated hydrocarbons  are the compounds in which there is a single bond between the carbon atoms.They are also called alkanes and have the general formula C_nH_2n+2

Cycloalkanes contain single bond between the carbon atoms,they form ring structures and have the general formula C_nH_2n

aromatic hydrocarbon are not open chained. They are ring structures.they contain one or more benzene rings either fused or isolated in their molecules.

n-pentane CH₃CH₂CH₂CH₂CH₃

2-Methylbutane CH₃CH(CH₃)CH₂CH₃

2,2-Dimethylpropane CH₃CH(CH₃)₂CH₃

Wurtz reaction is used for the preparation of alkanes from alkyl halides in the presence of sodium and dry ether.For example: CH₃Br + 2Na +BrCH₃ ---------> CH₃CH₃ + 2NaBr

Thus two atoms of Na are used.

 conformational isomers are obtained by rotation about a carbon-carbon single bond.This results in infinite number of momentary arrangements of atoms in space.Hence for ethane infinite number of conformations are possible.

As molecular mass increases,the magnitude of van der Waals forces of attraction increases and hence boiling point increases accordingly.

Halogenation of alkanes is a substitution reaction because the hydrogen atoms are replaced by halogens in the presence of sunlight  to give the corresponding alkyl halides.The reaction follows free radical mechanism.

Alkenes are unsaturated hydrocarbons with atleast on double bond between the carbon atoms.Their general formula is C_nH_2n.