Q. \( \textbf{Lewis dot structure for } \mathrm{CH_3OH} \)

Let’s build the Lewis dot (Lewis structure) for methanol, \(\mathrm{CH_3OH}\), step by step.

Step 1: Count the total valence electrons

Determine how many valence (bonding) electrons all atoms contribute.

\(\mathrm{CH_3OH}\) contains:

• 1 carbon atom (\(\mathrm{C}\))
• 4 hydrogen atoms (\(\mathrm{H}\)): three on carbon and one on oxygen
• 1 oxygen atom (\(\mathrm{O}\))

Valence electrons per atom:

• \(\mathrm{C}\) has 4 valence electrons
• \(\mathrm{H}\) has 1 valence electron each
• \(\mathrm{O}\) has 6 valence electrons

Total valence electrons:

\[
\text{Total} = (1 \times 4) + (4 \times 1) + (1 \times 6)
\]
\[
\text{Total} = 4 + 4 + 6 = 14
\]

So, you must place 14 total valence electrons in the Lewis structure.

Step 2: Determine the skeleton (which atoms are connected)

In methanol, the connectivity is known from the formula structure:

• Carbon is bonded to three hydrogens: \(\mathrm{C-H}\), \(\mathrm{C-H}\), \(\mathrm{C-H}\)
• Carbon is bonded to oxygen: \(\mathrm{C-O}\)
• Oxygen is bonded to one hydrogen: \(\mathrm{O-H}\)

So the skeleton is:

\(\mathrm{H_3C-OH}\)

That means we initially place bonds:

• Three \(\mathrm{C-H}\) single bonds
• One \(\mathrm{C-O}\) single bond
• One \(\mathrm{O-H}\) single bond

Each single bond uses 2 electrons.

Total electrons used in 5 single bonds:

\[
5 \text{ bonds} \times 2 = 10 \text{ electrons}
\]

But we have 14 electrons total, so we still have:

\[
14 – 10 = 4 \text{ electrons remaining}
\]

Step 3: Place remaining electrons (lone pairs)

Remaining electrons come as nonbonding pairs (lone pairs).

Oxygen usually forms a stable octet by keeping lone pairs. Oxygen has 4 remaining electrons to place.

Place them as two lone pairs on oxygen.

That uses all 4 remaining electrons.

Step 4: Check octets/duets

Hydrogen (4 hydrogens total):

• Each hydrogen has one bond, so each has a filled duet (2 electrons).

Carbon:

• Carbon has 4 bonds total (three \(\mathrm{C-H}\) bonds and one \(\mathrm{C-O}\) bond).
• So carbon has an octet worth of electrons around it (8).

Oxygen:

• Oxygen has two single bonds (one to carbon and one to hydrogen).
• And it has two lone pairs.
• That gives oxygen an octet (8 electrons total around oxygen).

Final Lewis dot structure for \(\mathrm{CH_3OH}\)

Lewis structure (showing lone pairs on oxygen):

\(\mathrm{H\ \ \ \ \ \ \ \ \ \ \ \ H}\\
\mathrm{|}\\
\mathrm{H-C-O-H}\\
\mathrm{}} \)

More explicitly in line form with lone pairs:

H—C—O—H, with oxygen having two lone pairs.

In a clear textual representation:

\(\mathrm{CH_3OH}\) has three \(\mathrm{C-H}\) single bonds, one \(\mathrm{C-O}\) single bond, one \(\mathrm{O-H}\) single bond, and oxygen carries two lone pairs.

Electron count summary (to confirm)

• 5 single bonds \(\rightarrow 10\) electrons
• 2 lone pairs on oxygen \(\rightarrow 4\) electrons
• Total \(\rightarrow 14\) electrons ✔