An unsaturated hydrocarbon 'A' adds two molecules of `H_(2)` and on reductive ozonolysis gives butane-1, 4-dial, ethanal and propanone. Give the structure of 'A' , write its IUPAC name and explain the reactions involved.

Explanation

Two molecules of hydrogen add on A and this means that .A. is either an alkadiene or alkyne. On reductive ozonolysis, .A. gives three fragments and one of these is dialdehyde. Hence, the molecule has broken down at two sites. Therefore .A. has two double bonds. The three fragments obtained on reductive ozonolysis are :
`underset("Butane-1,4-dial")(OHC -CH_(2)- CH_(2)- CHO, CH_(3)CHO) underset("Ethanal")(CH_(3)CHO)`
The structure of .A. as deduced from three fragments is

The hydrocarbon can be written by removing oxygen atoms and writing double bonds between the carbonyl carbon
`overset(8)CH_(3)- overset(7)CH= overset(6)CH-overset(5)CH_(2)- overset(4)CH_(2)- overset(3)CH= overset(2)underset(CH_(3))underset(|)C-overset(1)CH_(3)`
UPAC name : 2-Methylocta-2, 6-diene
Reactions are