Note that these types of questions are often the most difficult on the examination. This is because they are holistic in that they require a good understanding of the reactions and the concepts and the ability to apply those concepts. They can't be memorised, they require understanding and ability to apply. Hence they help discriminate those who truly understand from those who have memorised and will soon forget.

A schematic of the solution is shown below. The information from the question is given in black. Deductions directly from this information are given in red. Points that provide potential key information are shown in green which leads to the structures.... the path is 1-hexyne to G to D then B, C, A and/or E/F to A and work them all out. There are, of course, other possible thought pathways.

Common mistakes:

• Did not know the product of the reaction between 1-hexyne and Hg2+,H+,H2O; e.g. saying that it a carboxylic acid instead of a methyl ketone or the enol as the product.

• Could not draw / recognize ozonolysis products

• Showing radical substitution with Br at primary or secondary positions in B when it would have been tertiary due to radical selectivity

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