Coding for branched chains
4 marks · NormalThe compound below has five carbon atoms in its longest chain. It is shown with numbered carbon atoms, and a side chain:
Write the name of the longest chain.
Identify the type and position of the side chain shown.
Give the full IUPAC name of the compound.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) pentane
(b) methyl group at position 3
(c) 3-methylpentane
Common mistakes: wrongly numbering from the incorrect end; missing the side chain type; incorrect IUPAC order
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly gives the name of the five-carbon chain as 'pentane'.
M1 (b) · 1 mark · Correctly identifies the side chain as a methyl group.
A1 (b) · 1 mark · Correctly gives the position as carbon 3.
B1 (c) · 1 mark · States the correct IUPAC name as '3-methylpentane'.
Worked solution
a) The longest continuous chain has 5 carbons, which is 'pentane'.
b) The side chain is a methyl group () attached to carbon 3.
c) The full IUPAC name is 3-methylpentane.