1. Organic Chemistry

2. Alkynes -Contain carbon-carbon triple bonds -sp-Hybridization -Unsaturated hydrocarbons -C n H 2n-2

3. IUPAC names -Alkynes name are similar to that for alkanes. …………..ane …………..yne

4. Physical Properties of Alkynes 1.C2-C4GAS C5-C17LIQUID  C18SOLID mp.bp. 2. Ethyne C 2 H 2 80.8-84.0 Propyne C 3 H 4 101.5-23.2 Butyne C 4 H 6 125.78.1

5. Why ??? 12 bp Cis-isomer  trans-isomer

6. Isomers Same formula Different structure Different molecule with different properties – must have a different name! Isomers of C 4 H 6

7. Isomers of C 5 H 8

8. Reaction of Alkyne 1. Combustion reaction 2. Addition reaction -Hydrogenation reaction (H 2 )Ni, Pd, Pt cat. -Halogenation reaction (X 2 / CCl 4 )

9. -Hydrohalogenation reaction (HBr) -Hydration reaction (H 2 O) Condition……………….

10. 3. Oxidation reaction

11. Aromatic Compound 1.The structure must be cyclic, containing some number of conjugated pi bond. 2.HUCKEL’ s rule (4n+2; n=0,1, 2,3,4…) aromatic system 2, 6, 10, 14…)