Which of the following statements is false? (i) A D enantiomers rotates the plane of polarized light to the right and an L enantiomer to the left (ii) Conversion of an erythro to a threo stereoisomer always occurs by inversion at one chiral C. (iii) A racemate can be distinguished from a maso or an achiral compound by an attempted resolution (iv) Racemizatio of an enantiomer can only occur by breacking of a least one bond to the chiral center (v) A reaction catalyzed by an enzyme always gives an optically active product.

Which of the following statements is false? (i) A D enantiomers rotat

1.	Which of the following statements is false? (i) A D enantiomers rotates the plane of polarized light to the right and an L enantiomer to the left (ii) Conversion of an erythro to a threo stereoisomer always occurs by inversion at one chiral C. (iii) A racemate can be distinguished from a maso or an achiral compound by an attempted resolution (iv) Racemizatio of an enantiomer can only occur by breacking of a least one bond to the chiral center (v) A reaction catalyzed by an enzyme always gives an optically active product.
Answer» (i),(ii),(iii),(iv),(v) (i),(iii),(v) (i),(v) (ii),(iii),(iv) SOLUTION :(i) is false because the terms `D` and `L` do not REFER to the sign of ROTATION. They refer to the configuration of a stereoisomer relative to that of `D`(or`L`)-glyceraldehyde. Moreover `D` and `L` steroisomers are not necessarily enantiomers. The statement that `D` and `L` steroismers are enantiomers is ture only for a compound with one chiral carbon. Consider the conversion of the `D` compound above to the `L` compound, a different diasteromer i9s formed. (ii) is true because changing the configuration at one of the chiral carbon atoms converts one diastereomer to the other (iii) is true because UNLIKE a racemate, meso and chiral compounds cannot be resolved as they do not consist of enantiomers. (iv) is true because only by breaking a bond configuration is changed (v) is false because the product could be meso or chiral