– Molecular formula = C2H6 – Molecular mass = 30 – Empirical formula = CH3 – Empirical formula mass = 15 – State: Gas at room temperature. – Occurrence: Ethane occurs along with methane in natural gas and gases from oil-wells. It is also present in coal gas in very small quantity.
ORBITAL STRUCTURE OF ETHANE
Composition of ethane molecule: Ethane molecule consists of two carbon atoms and six H-atoms (C2H6 ). Nature of Hybridization: In ethane each C-atom is Sp3-hybridized containing four Sp3-hybrid orbitals. One s-orbital and three p-orbitals (px, py, pz) undergo Sp3-hybridization to produce four Sp3-hybrid orbitals for each carbon atom. Sigma bond formation: Out of four Sp3-hybrid orbitals one Sp3-hybrid orbital of one C-atom overlaps with one s-orbital of H-atom to produce three sigma bonds and the last overlaps with one Sp3-orbital of other C-atom to produce a sigma bond between two C-atoms. Geometry of ethane:
Ethane molecule is arranged in tetrahedral geometry in which central carbon atoms are surrounded by H-atoms in three dimensions.
HCH bond angle is 109.5o. Bond length: C-H bond length is 1.09Ao and C-C bond length is 1.54Ao.
METHODS OF PREPARATION
FROM WURTZ REACTION
2CH3I + 2Na C2H6 +2NaI
FROM GRIGNARD’S REAGENT
Ethane may be obtained by the hydrolysis of ethyl magnesium iodide. C2H5-Mg-I + HOH C2H6 + Mg-OH-I
FROM ETHYL IODIDE
C2H5-I + 2[H] C2H6 + HI
BY THE CATALYTIC REDUCTION OF ETHYL IODIDE
C2H5-I + H2 C2H6 + HI
Ethane burns in air or oxygen with a non-luminous flame to produce carbon dioxide and water. It is an exothermic
2C2H6 + 7O2 4CO2 + 6H2O + HEAT
Replacement of halogen with H-atom of an organic compound is called Halogenation. It is a substitution reaction. CHLORINATION:
C2H6 + Cl2 C2H5Cl C2H4Cl2+ Cl-CH2-CH2-Cl
It is colorless gas. Its boiling point is -89oC. It is sparingly soluble in water.