Which of the following is an unsaturated hydrocarbon?
- Methane (CH4)
- Propane (C3H8)
- Ethene (C2H4)
- Butane (C4H10)
Show answer and solution
Correct answer: C. Ethene (C2H4)
1. Saturated hydrocarbons have only C-C single bonds.
2. Methane, propane and butane are alkanes (CnH(2n+2)).
3. Ethene has a C=C double bond (C2H4) and follows CnH(2n).
4. So ethene is the unsaturated hydrocarbon here.
5. The double bond makes it more chemically reactive than alkanes.
_Source: syllabus Science Ch 4 'Carbon and its Compounds' (byjus.com extract)_