Correct Answer - Option 4 : Yellow
- The unsaturated hydrocarbons like alkenes, alkynes are aromatic hydrocarbons that partially burned with a yellow sooty flame.
- It is due to the incomplete combustion of the hydrocarbon in air.
- A large amount of carbon does not completely oxidize in the air and gives sooty flame.
- The saturated hydrocarbons burn with a Blue colour non-sooty flame.
Alkanes are saturated hydrocarbons and classified as a type of aliphatic hydrocarbon.
Hexane is a type of Alkanes that burns with a blue non-sooty flame. Hence option 2 is correct.
- The blue flame emerges when the complete combustion of carbon takes place.
Hydrocarbons are the derivates of the carbon and hydrogen compounds. In organic chemistry, Hydrocarbons are classified into three:-
1. Alkanes: These are represented by Single Bond between two carbons.
- The chemical formula CnH2n+2
- the first member of the alkane group - Methane (CH4)
- Symbolic representation of alkanes is —C—C—
Methane is colorless, odorless, flammable gas. it is used primarily as fuel to make heat and light. it is used in the manufacturing of organic chemicals.
2. Alkenes: These are represented by Double Bond between two carbons
- The chemical formula CnH2n
- The first member of the alkene group - Ethene (C2H4)
- Symbolic Representation of alkenes is —C=C—
- Ethene is used in the production of ethylene glycol ( 1,2-ethanediol ) an automotive anti-freezing agent, used in the production of polymers such as polythene, polyvinyl chloride, polystyrene.
3. Alkynes: These are represented by a Triple Bond between two carbons
- The chemical formula CnH2n-2
- The first member of the alkyne group - Ethyne (C2H2)
- Symbolic representation of alkynes is —C=C—
Ethyne is also called Acetylene which is used in portable lighting, welding, and cutting, production of Chemicals.