Reactions of organic compounds

Organic compounds undergo different types of chemical reactions, including:

• Oxidation
• Substitution
• Addition
• Elimination

1. Oxidation Reactions

• Reaction with oxygen $(O₂)$ to form carbon dioxide $(CO₂)$ and water $(H₂O).$
• Exothermic (releases energy).
• General reaction: $\text{alkane} + O_2 \rightarrow CO_2 + H_2O + \text{energy}$

2. Substitution Reactions

• Occur when saturated compounds (alkanes) react.
• A hydrogen atom is replaced by another atom (e.g., halogens).
• Produces saturated products.
• Slow reaction and requires heat or UV light to proceed.

Example: Halogenation

$\text{alkane} + \text{halogen} \xrightarrow{\text{UV light or heat}} \text{haloalkane} + HX$

3. Addition Reactions

• Occur in unsaturated compounds (alkenes and alkynes).
• Atoms add across the double/triple bond, breaking the multiple bond.
• Produces saturated products.
• Faster than substitution reactions.

Types of Addition Reactions

Reaction	Conditions	Reaction Equation
Hydrogenation (addition of $H₂)$	Catalyst: $Pt, Pd, or Ni$	$Alkene + H₂ → Alkane$
Halogenation (addition of $X₂$)	No catalyst	$Alkene + X₂ → Dihaloalkane$
Hydrohalogenation (addition of $HX$)	No catalyst	$Alkene + HX → Haloalkane$
Hydration (addition of $H₂O$)	$H₂SO₄$ catalyst	$Alkene + H₂O → Alcohol$

Markovnikov's Rule: In addition of $H-X,$ the $H$ bonds to the carbon with more hydrogen atoms.

4. Elimination Reactions

• Atoms or groups are removed, forming double or triple bonds.
• Converts saturated compounds into unsaturated ones.
• Endothermic (requires heat).

Types of Elimination Reactions

Reaction	Conditions	Reaction Equation
Cracking	Catalyst, heat	$Alkane → Alkene + Alkane$
Dehydrohalogenation	NaOH (alcoholic), heat	$Haloalkane → Alkene + HX$
Dehydration	$H₂SO₄,$ heat	$Alcohol → Alkene + H₂O$