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h
H 3 C CH CH 3 + Cl 2 H 3 C CH CH 3 + HCl
2
Cl

Alkenes (unsaturated hydrocarbons in the ethylene
series) are organic compounds in which the molecules have
one double bond. The general formula is CnH2n. They are
characterized by joining reactions. In the case of
asymmetric alkenes, the addition of compounds of the type
HX, where X = Hal, OH, OSO3H, occurs according to the
Markovnikov rule: Hydrogens joins the most hydrogenated
Carbon atom:

H C CH CH + HX H C CH
2 3 3 CH 3
X

Alkenes can be readily oxidized with various oxidizing
agents, and perhaps oxidation without breaking the double
bond and with a gap, for example, solutions of KMnO 4,
H 2O 2:

KMnO H SO+
4 2 4
H C CH CH CH O + O CH CH
2 3 2 3
[O]
H C CH CH + KMnO + H O H C CH CH + MnO + KOH
2 3 4 2 2 3 2
The progress
OH OH

Against Alcano and alkene to the solution bromine
water and potassium permanganate

3
In one test-tube pour 2-3 cm bromine water and 2-3
3 3
cm of 0.5 % KMnO 4 solution. Pour 2-3 cm of hexane to
3
each test tubes, to another pair of 2-3 cm 1-hexene. The