Question

The number of structural and configurational isomers of a bromo compound, $C_5{H}_{9}Br$, formed by the addition of $HBr$ to $2-pentyne$ respectively $x$ and $y$. Find the value of $x+y$.

Answer 1

When $HBr$ adds on to $2-pentyne$ it gives two structural isomers i.e., $I$ and $II$.

Each one of these (i.e., I and II) exsits as a pair of geometrical isomers (cis and trans). Thus, we have two structural and four configurational isomers.