a) Lewis Dot Structure
To draw the Lewis Dot Structure for CH3CH2OH (ethanol), start by counting the total number of valence electrons. Carbon (C) has 4 valence electrons, hydrogen (H) has 1, and oxygen (O) has 6. Therefore, for ethanol:
Total valence electrons = (2 x 4) + (6 x 1) + (6) = 14 electrons.
In the structure, each carbon is bonded to the appropriate number of hydrogens to fulfill the tetravalency (four bonds for carbon). The hydroxyl group (-OH) is attached to the second carbon. The resulting structure shows two carbons connected to each other, with hydrogen and hydroxyl groups filling their bonding requirements.
b) Second Structure with Bonds Drawn
Here’s a more explicit representation showing the bonds:
H H H
| | |
H – C – C – O – H
| |
H H
This structure clearly shows each bond connecting the atoms. Single lines represent single bonds and indicate the sharing of a pair of electrons between the atoms.
c) Is the Molecule Polar or Nonpolar?
The molecule CH3CH2OH is polar. This polarity arises mainly due to the presence of the hydroxyl (-OH) group. The difference in electronegativity between the oxygen and the hydrogen atoms leads to an uneven distribution of electron density, causing the molecule to have a partially negative charge near the oxygen and a partially positive charge near the hydrogen atoms. This creates a dipole moment in the molecule.
Therefore, the structure of ethanol is not symmetrical enough to cancel out these polar bonds, which contributes to its overall polar nature.