Describe any two methods of preparation of ethane with equations, give any three reactions of ethane.

Explanation

Methods of preparation of ethane:
1.Decarboxylation of sodium propionate: Ethane is prepared by heating sodium propionate with soda lime.
(Sodi lime =NaOH+CaO)
`CH_(3)-CH_(2)-COONa+NaOHunderset(Delta)overset(CaO)(to)C_(2)H_(6)+Na_(2)CO_(3)`
2. Wurtz reaction: Ethane is prepared by heating methyl iodide with sodium metal in dry ether.
`CH_(3)I+2Na+ICH_(3)underset("ether")overset("Dry")(to)CH_(3)-CH_(3)+2NaI`
Properties of ethane:
1. Substitution reaction: Reactions in which an atom or group present in a compound is replaced by another atom or group are known as substitution reactions.
a. Halogenation : In the presenc of sunlight or UV radiation ethane undergoes halogenation. The H atoms of alkene are successively replaced by the halogen atoms.
`C_(2)H_(6)underset(Cl_(2))overset(hv)(to)C_(2)H_(5)Clunderset(Cl_(2))overset(hv)(to)C_(2)H_(4)Cl_(2)underset(Cl_(2))overset(hv)(to)C_(2)H_(3)Cl_(3)underset(Cl_(2))overset(hv)(to)C_(2)H_(2)Cl_(4)`
`underset(Cl_(2))overset(hv)(to)C_(2)HCl_(5)underset(Cl_(2))overset(hv)(to)C_(2)Cl_(6)`
b. Nitration: Ethane reacts with vapours of `HNO_(3)` at `400^(@)C` and forms nitroethane.
`C_(2)H_(6)+HNO_(3)overset(400^(@)C)(to)C_(2)H_(5)NO_(2)+H_(2)O`
2. Combustion: Complete oxidation of the compound in air is called combustion. It gives `CO_(2)` and `H_(2)O` along with liberationof heat.
`C_(2)H_(6)+7/2O_(2)to2CO_(2)+3H_(2)O+` energy