Question

why 2 butanol is optically inactive?

Answer 1

It is normally found as an equal mixture of the two stereoisomers — a racemic mixture. As we know a racemic misture is optically inactive, so, (±)2-Butanol is optically inactive.

Answer 2

This is because it consist of both dextrorotatory i.e(+)& laevorotatory i.e (-)due to which it result in the formation of racemic mixture according to which net rotation of plane polarized light towards right is cancelled by the left one.This makes the butanol solution to becomes optically inactive.