Isoprene is a diene. How are the positions of double bonds located?

Explanation

The position of multiple bonds present between carbon atoms can be located by ozonolysis.
Isoprene is an unsaturated hydrocarbon with molecular formula `C_(5)HH_(8)`.
One mole of isoprene on ozonolysis gives two moles of methanal and one mole of 2-oxopropanal. Hence isoprene has two double bonds on terminal carbon atoms and a branch on one of the doubly bonded carbon atoms.
Arranging the ozonolysis products in a sequence, we get the products.
`underset(darrO_(3),H_(2)O,Zn)(H_(2)C=underset(CH_(3))underset(|)(C)-CH=CH_(2))`
`H-overset(H)overset(|)(C)=O+O=underset(CH_(3))underset(|)(C)-overset(H)overset(|)(C)=O+O=overset(H)overset(|)(C)-H`
Hence isoprene is 2-methyl-1,3-butdiene.