explain the polarity in ethanol?
why it is polar molecule?
thanks
A polar molecule is any molecule that tends to have more negative charges (electrons) on one end and more positive charges (protons in nuclei) in the other, even though the total number of protons and electrons are the same.
The ethanol molecule has a polarity of 25.7 Debyes. That number is called the dipole moment and is a measure of the separation of positive and negative charges in the molecule. The polarity of ethanol is caused by the lack of symmetry resultng from having an OH group stuck at one end of a C=C "backbone" and an H atom at the
other.
I will attempt to draw the molecule
..H.H
..| |
H-C=C-OH
..| |
..H H
One Debye of dipople moment equals 3.33564 × 10^−30 coulomb-meter
The molecule didn't turn out the way I wanted. Here is another attempt
...H..H
...|..|
H-C=C-OH
...|..|
...H..H
The vertical lines | are supposed to connect each C atom with one H atom above and one below
I have been informed by DrBob222 that the structure of ethanol is actually
CH3CH2OH, rather than what I wrote. Nevertheless, it is true that an asymmetrical structure is the source of the diple moment.
Chemistry is not my field of expertise; I apologize for the error
To understand the polarity of ethanol, we need to analyze its molecular structure. Ethanol (C2H5OH) consists of two carbon atoms (C), six hydrogen atoms (H), and one oxygen atom (O).
The oxygen atom in ethanol is more electronegative than the carbon and hydrogen atoms. Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond. In ethanol, oxygen has a higher electronegativity than carbon.
In the ethanol molecule, the oxygen atom attracts electrons more strongly than the carbon and hydrogen atoms. This unequal sharing of electrons creates a partial negative charge (δ-) on the oxygen atom and partial positive charges (δ+) on the carbon and hydrogen atoms.
The molecular structure of ethanol also plays a role in its polarity. Ethanol has a bent or V-shape geometry due to the spatial arrangement of the atoms. The oxygen atom is located at one "end" of the molecule, while the carbon and hydrogen atoms form the other "end". This uneven distribution of charge across the molecule makes ethanol a polar molecule.
The polarity of ethanol allows it to dissolve in polar solvents like water. The partial positive charges on the carbon and hydrogen atoms in ethanol can interact with the partial negative charges of water molecules, forming hydrogen bonds. This leads to ethanol's ability to mix and dissolve in water.
In summary, ethanol is a polar molecule due to the difference in electronegativity between the oxygen and carbon/hydrogen atoms, as well as its bent molecular structure.