The number of structural and configurational isomers of a bromo compound, `C_5H_9Br`, formed by the addition of `HBr` to 2-pentyne respectively, is:

Options

A. 1 and 2
B. 2 and 4
C. 4 and 2
D. 2 and 1

Answer

B

Explanation

`underset("Pent-2-yne")(CH_(3)-C-=CH-CH_(3)overset(HBr)to `
`CH_(3)-overset(Br)overset(|)(C)=CH-CH_(2)-CH_(3)+CH_(3)-CH=overset(Br)overset(|)(C)-CH_(2)-CH_(3)`
Thus, there are two structural isomers and each of these structural isomers can show geometrical isomerism. As such there are four configuration isomers.