A12. Which ONE of the following statements is INCORRECT?(A) A racemic mixture is a 1:1 mixture of two enantiomers.(B) Enantiomers have identical physical properties except for theirinteraction with plane polarised light.(C) Enantiomers of the same compound rotate the plane of polarised lightin the same direction but by differing amounts.(D) Enantiomers can have very different biological properties.(E) Enantiomers are isomers that are non-superimposable mirror images.

Step 1: Understand the problem

The problem is asking us to identify the incorrect statement about enantiomers.

Step 2: Evaluate each statement

(A) A racemic mixture is a 1:1 mixture of two enantiomers. - This statement is correct. A racemic mixture is indeed a 1:1 mixture of two enantiomers.

(B) Enantiomers have identical physical properties except for their interaction with plane polarised light. - This statement is also correct. Enantiomers are stereoisomers that are mirror images of each other and have identical physical properties, except for the direction in which they rotate plane-polarized light.

(C) Enantiomers of the same compound rotate the plane of polarised light in the same direction but by differing amounts. - This statement is incorrect. Enantiomers of the same compound rotate the plane of polarized light in opposite directions, not the same direction.

(D) Enantiomers can have very different biological properties. - This statement is correct. While enantiomers have identical physical properties, they can interact differently with biological molecules and therefore can have different biological properties.

(E) Enantiomers are isomers that are non-superimposable mirror images. - This statement is correct. Enantiomers are indeed non-superimposable mirror images of each other.

Step 3: Choose the incorrect statement

The incorrect statement is (C) Enantiomers of the same compound rotate the plane of polarised light in the same direction but by differing amounts.