Naming organic compounds
2 marks · HardThe condensed structural formula of a hydrocarbon is given below:
State the IUPAC name for this compound.
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pent-2-ene
Also accept: 2-pentene
Common mistakes: pent-3-ene; pent-1-ene; pentene
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Marking points
M1 · 1 mark · Identifies 5 carbons in the longest chain and the presence/position of double bond (between C2–C3).
A1 · 1 mark · Gives the correct IUPAC name: pent-2-ene (or 2-pentene).
Worked solution
The structure has five carbon atoms in a chain, so the parent name is pent-.
The compound has a double bond between the second and third carbon atoms from the left, so it is an 'ene'. The double bond is at position 2.
The IUPAC name is pent-2-ene.