Which of the following is 'not' true about enantiomers?
Show Hint
- They have the same chemical reactivity.
- They have the same specific rotation.
- They have the same melting or boiling point.
- They have the same refractive index.
The Correct Option is B
Solution and Explanation
Enantiomers are non-superimposable mirror images. They share almost all physical and chemical properties (melting point, boiling point, density, refractive index, solubility, chemical reactivity in an achiral environment).
Step 1:
The one property in which enantiomers differ is their behaviour towards plane polarised light. They rotate the plane of polarised light by an equal magnitude but in opposite directions (one is (+) / dextrorotatory, the other is (−) / laevorotatory).
Step 2:
So their specific rotations are equal in size but opposite in sign, which means they do NOT have the same specific rotation. The statements in options (A), (C) and (D) are true for enantiomers.
Answer: Option (2) — They have the same specific rotation is the statement that is NOT true.
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