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2. Un-saturated Hydrocarbons (Alkenes/Alkynes)-

a. Combustion-
Like most other hydrocarbons, unsaturated hydrocarbons can undergo-combustion
reactions that produces carbon dioxide and waterduring complete combustion but,
burns with a sooty flame usually as it undergoes incomplete combustion due to a
higher percentage of carbon presentin them.

The reaction equation is: C xH y + y+2x2O 2 → yH 2O + xCO.

For example combustion of propene-
Smoke is produced when propene is burned in air due to incomplete combustion.
Incomplete combustion takes place because the percentage of carbonis high
inAlkenes.

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