Organic Chemistry: The Basics
🌱 Why Organic Chemistry Matters
Organic compounds are everywhere in life! They make up DNA 🧬, proteins in your blood/muscles, clothes 👕, fuels ⛽, plastics, dyes, and medicines 💊. This branch of chemistry studies carbon-containing compounds and their reactions.
⏳ Quick History Lesson
- 1780s: Scientists thought organic compounds only came from living things (plants/animals)
- 1828: Friedrich Wöhler proved this wrong! He made urea (an organic compound in urine) from inorganic ammonium cyanate:
$$\text{NH}_4\text{CNO} \xrightarrow{\text{heat}} \text{NH}_2\text{CONH}_2$$ (Ammonium cyanate → Urea) 🔥 - 1845-1856: Kolbe made acetic acid, Berthelot made methane – confirming organic compounds can be lab-synthesized!
🔑 Carbon’s Superpowers
Carbon atoms:
- Always form 4 bonds (tetravalence)
- Link together in chains (catenation)
- Bond with H, O, N, S, P, halogens
🔮 Shapes & Hybridization
Carbon mixes its orbitals to form different shapes:
| Hybridization | Shape | Example | Bond Strength |
|---|---|---|---|
| sp³ | Tetrahedral (like a pyramid) | CH4 | Stronger bonds → more s-character |
| sp² | Trigonal planar (flat triangle) | H2C=O | Medium strength |
| sp | Linear (straight line) | HC≡N | Strongest bonds |
Fun fact: More s-character = stronger bonds + higher electronegativity!
π Bonds Explained
- Formed by sideways overlap of p-orbitals ↔️
- Lock molecules in a flat shape (all atoms in same plane)
- Restrict rotation around double bonds (C=C) 🔒
- Very reactive – electrons are exposed above/below the bond plane!
💡 Practice Problems
Problem 1: Count σ and π bonds in HC≡CCH=CHCH3
Solution: σC-C: 4, σC-H: 6, πC≡C: 2, πC=C: 1
Problem 2: Hybridization in CH3CN?
Solution: CH3 (sp³) + CN (sp)
🚀 Top 3 NEET Concepts
- Hybridization & Shapes: Know sp³/sp²/sp → tetrahedral/trigonal/linear shapes
- π-Bond Behavior: Restricted rotation + high reactivity of double/triple bonds
- Wöhler’s Experiment: First organic synthesis (urea from ammonium cyanate)
