Draw the Lewis dot structure for ethanol, CH3CH2OH, and dimethyl ether, CH3OCH3. Determine the overall geometry and molecular geometry around the oxygen atom in each, and identify the molecules as being polar or nonpolar.
CH3, OCH3, CH3CH2OH
Compound:
Dot Structure:
Overall Geometry: (around the O atom)
Molecular Geometry: (around the O atom)
Polar/Nonpolar:
The correct answer and explanation is:
Here is the Lewis dot structure and molecular details for ethanol (CH₃CH₂OH) and dimethyl ether (CH₃OCH₃):
Ethanol (CH₃CH₂OH)
- Dot Structure: Ethanol consists of a two-carbon chain (CH₃CH₂) bonded to a hydroxyl (-OH) group. The oxygen atom in the -OH group has two lone pairs.
- Overall Geometry (around oxygen): The oxygen in ethanol is tetrahedral because it forms two single bonds (to hydrogen and carbon) and has two lone pairs.
- Molecular Geometry (around oxygen): The electron domain geometry is tetrahedral, but the molecular geometry is bent (angular) due to the two lone pairs on oxygen.
- Polarity: Polar. Ethanol is polar because of the highly electronegative oxygen, which creates a dipole moment. The hydroxyl (-OH) group allows hydrogen bonding, making it highly soluble in water.
Dimethyl Ether (CH₃OCH₃)
- Dot Structure: Dimethyl ether has an oxygen atom single-bonded to two methyl groups (CH₃). Oxygen has two lone pairs.
- Overall Geometry (around oxygen): Tetrahedral, due to the two bonding groups and two lone pairs on oxygen.
- Molecular Geometry (around oxygen): Bent (angular), like ethanol, because the lone pairs push the bonded atoms down.
- Polarity: Polar. Even though the carbon-oxygen bonds are symmetrical, oxygen is more electronegative, creating a dipole moment. However, unlike ethanol, dimethyl ether cannot form hydrogen bonds (due to the lack of an -OH group), making it less soluble in water.
Both molecules are polar, but ethanol is more polar due to hydrogen bonding.
Now, I’ll generate the Lewis dot structure image.
Here is the Lewis dot structure diagram comparing ethanol (CH₃CH₂OH) and dimethyl ether (CH₃OCH₃). The image illustrates the molecular structures with lone pairs on oxygen and their bent geometry.
Key Takeaways:
- Ethanol (CH₃CH₂OH) has a hydroxyl (-OH) group, making it strongly polar and capable of hydrogen bonding.
- Dimethyl ether (CH₃OCH₃) has an oxygen bonded to two methyl groups, making it polar but unable to form hydrogen bonds.
- Both molecules have a bent geometry around oxygen due to lone pairs.
- Ethanol is more soluble in water due to its hydrogen bonding ability.
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