OC-01 Visual Guide — Reaction Pathways, SMILES Structures, and Data Tables — Summary

Hybridization at a Glance

Hybridization	SMILES Example	Geometry	Bond Angle	% s-char
sp3	`C` (methane)	Tetrahedral	109.5°	25%
sp2	`C=C` (ethene)	Trigonal planar	120°	33.3%
sp	`C#C` (ethyne)	Linear	180°	50%

SMILES: Key Functional Groups

Methane: C
Ethane: CC
Ethene: C=C
Ethyne: C#C
Ethanol: CCO (SMILES: CCO — ethanol)
Ethanoic acid: CC(=O)O (SMILES: CC(=O)O — ethanoic acid)
Acetone: CC(=O)C (SMILES: CC(=O)C — propan-2-one)
Ethanal: CC=O (SMILES: CC=O — ethanal)
Methylamine: CN (SMILES: CN — methylamine)

Reaction Pathway: Bond Fission Leads to Intermediates

Covalent Bond
     |
     +-- Homolytic fission (equal) --> Free Radicals (R·)
     |                                  Stability: 3° > 2° > 1° > $CH_{3}$·
     |
     +-- Heterolytic fission (unequal) --> Carbocation ($R^{+}$)  [C loses electrons]
                                           Stability: 3° > 2° > 1° > $CH_{3}^{+}$
                                        --> Carbanion ($R^{-}$)    [C gains electrons]
                                           Stability: $CH_{3}^{-}$ > 1° > 2° > 3°

Reaction Type Pathway

$CH_{3}$ OH + HBr --[ $\Delta$ ]--> $CH_{3}$ Br + $H_{2}O$ (Substitution — OH replaced by Br)

$CH_{2}$ = $CH_{2}$ + HBr --[room temp]--> $CH_{3}$$CH_{2}$ Br (Addition — π bond consumed)

$CH_{3}$$CH_{2}$ Br + KOH --[alc., $\Delta$ ]--> $CH_{2}$ = $CH_{2}$ + KBr + $H_{2}O$ (Elimination — π bond formed)

Electronic Effects Map

$\text{Inductive Effect} \xrightarrow{\text{through } \sigma \text{ bonds}} \text{decreases with distance}$

$\text{Mesomeric Effect} \xrightarrow{\text{through conjugated } \pi} \text{resonance delocalization}$

$\text{Hyperconjugation} \xrightarrow{\alpha\text{-C-H} \sigma \rightarrow \text{empty p or }\pi} \text{no-bond resonance}$

Intermediate Stability: Visual Comparison

Intermediate	Most Stable	Least Stable	Key Reason
Carbocation $R^{+}$	3° ( $CH_{3}$ )_{3} $C^{+}$	$CH_{3}^{+}$	+I + hyperconjugation stabilize $C^{+}$
Carbanion $R^{-}$	$CH_{3}^{-}$	3° ( $CH_{3}$ )_{3} $C^{-}$	+I destabilizes $C^{-}$ (pushes onto negative C)
Free Radical R·	3° ( $CH_{3}$ )_{3}C·	$CH_{3}$ ·	Hyperconjugation + +I stabilize radical

Yield Formula (for reaction calculations)

$\text{yield} = \frac{\text{actual moles of product}}{\text{theoretical moles of product}} \times 100\%$

Methane Hybridization Diagram (Wikimedia Commons)

Methane sp3 tetrahedral structure

sp3 hybridization — methane tetrahedral geometry, 109.5° bond angles

Ethene sp2 structure

sp2 hybridization — ethene trigonal planar, 120° bond angles, one π bond