Which of the following is an acceptable Lewis structure for methanol (CH3OH)? H H C O H H H C=O H H H
The Correct Answer and Explanation is:
The correct Lewis structure for methanol (CH₃OH) is the third option in the image (third from the top).
Correct Answer:
Third structure
Explanation:
Methanol (CH₃OH) is composed of:
- 1 carbon atom (C)
- 4 hydrogen atoms (H)
- 1 oxygen atom (O)
Step-by-step analysis:
- Carbon forms four bonds.
Carbon is in group 14 and has 4 valence electrons, so it forms 4 covalent bonds. In methanol, carbon is bonded to three hydrogen atoms and one oxygen atom. - Oxygen forms two bonds and has two lone pairs.
Oxygen is in group 16 and has 6 valence electrons. In methanol, oxygen forms a single bond with the carbon and another single bond with a hydrogen atom (as in the hydroxyl group —OH). This leaves two lone pairs on the oxygen. - Each hydrogen forms one bond.
Hydrogen atoms have 1 valence electron and form only one bond.
The third option correctly shows:
- Carbon bonded to three hydrogens and to one oxygen.
- Oxygen bonded to one hydrogen and to the carbon.
- Two lone pairs on the oxygen.
Why other options are incorrect:
- First option: Oxygen is not bonded to hydrogen, which is incorrect for CH₃OH.
- Second option: Shows a double bond between carbon and oxygen, which is not how methanol is structured. That would resemble formaldehyde, not methanol.
- Fourth option: Oxygen is not bonded to hydrogen again, and there is a lone pair on carbon, which is incorrect since carbon does not carry lone pairs in this structure.
Thus, the third structure is the correct and acceptable Lewis structure for methanol.
