The incorrect statement regarding chirality is:

A racemic mixture shows zero optical rotation.

$\displaystyle \mathrm{S}_{\mathrm{N}} 1$ reaction yields $\displaystyle 1: 1$ mixture of both enantiomers.

The product obtained by $\displaystyle \mathrm{S}_{\mathrm{N}} 2$ reaction of haloalkane having chirality at the reactive site shows inversion of configuration.

Enantiomers are superimposable mirror images on each other.