The incorrect statement regarding chirality is :
 

• A

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

  Enantiomers are superimposable mirror images on each other.
   
• C

  A racemic mixture shows zero optical rotation.
   
• D

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

Hence, the correct answer is option: 'B'.