1-propanol or propan-1-ol (CH3CH2CH2OH) is a polar primary alcohol as it consists of a strongly polar hydroxyl (OH) functional group in it.
The strong dipole moments of C-O and O-H bonds do not get canceled with the weak dipole moments of C-H bonds.
CH3CH2CH2OH is a primary alcohol as the hydroxyl (OH) functional group is present at the terminal position i.e., attached to the C-atom carrying one alkyl chain only.
It is composed of 1 O-H bond, 1 C-O bond, 2 C-C bonds, and 7 C-H bonds.
Each C-C bond is purely non-polar as it consists of two identical carbon atoms having zero or no electronegativity differences.
A C-H bond is very weakly polar as the covalently bonded carbon (E.N = 2.55), and hydrogen (E.N = 2.20) atoms have an electronegativity difference of only 0.35 units.
A C-O bond is strongly polar as an electronegativity difference of 0.89 units is present between a carbon and an oxygen (E.N = 3.44) atom.
The O-H bond is extremely polar, having an electronegativity difference of 1.24 units between the oxygen and hydrogen atoms.
The shape of CH3CH2CH2OH w.r.t each C-atom is tetrahedral while that w.r.t the O-atom is bent, angular, or V-shaped.
2 lone pairs of electrons present on the oxygen atom lead to strong lone pair-lone pair and lone pair-bond pair electronic repulsions, which in turn distorts the shape and geometry of the molecule.
Oxygen being strongly electronegative attracts electrons from each C-H bond in addition to attracting the O-H and C-O bonded electrons.
The O-atom thus gains a partial negative charge (δ–), while the C and H-atoms gain partial positive charges (δ+ and/or δ++) to denote an extreme electron deficiency.
The strong O-H and C-O dipole moments do not get canceled equally.
The charged electron cloud stays non-uniformly distributed, which leads to an overall polar CH3CH2CH2OH molecule (net µ> 0).
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