Question

An unsaturated hydrocarbon ‘A’ adds two molecules of and on reductive ozonolysis
gives butane-l, 4-dial, ethanal and propanone. Give the structure of ‘A’, write its IUPAC name
and explain the reactions involved.

Answer 1

Two molecules of hydrogen add on ‘A’ this shows that ‘A’ is either an alkadiene or an alkyne. On reductive ozonolysis ‘A’ gives three fragments, one of which is dialdehyde. Hence, the molecule has broken down at two sites. Therefore, ‘A’ has two double bonds. It gives the following three fragments : OHC—CH2—CH2—CHO, CH3CHO and CH3—CO—CH3 Hence, its structure as deduced from the three fragments must be like the pic above.

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