MCQ: Racemic modification calculation of enantiomeric excess

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Fruit sugar Fructose ((L)-fructose) showed a specific rotation of is −92.4°, If the mixture of D and L fructose shows an optical rotation of -46.2°, what is the enantiomeric excess?

• L fructose 50% excess
• D fructose 50% excess
• L fructose 2% excess
• D fructose 2% excess

Which of the following mechanisms is most commonly associated with racemization of chiral compounds?

• SN1 reaction
• SN2 reaction
• E2 elimination
• Addition-elimination

Choose the correct statement

• lactic acid is a chiral compound and cannot undergo racemization in basic (Sol. NaOH) conditions
• Atrolactic acid DO NOT undergoes racemization in basic medium
• The magnitude of plane-polarized light rotation by D-lactic acid is greater than that of L-lactic acid.
• All of them are correct

Which of the following best describes a racemic mixture?

• A) A mixture of enantiomers with unequal proportions
• B) A mixture of diastereomers in a 1:1 ratio
• C) A 1:1 mixture of enantiomers that shows no net optical activity
• D) A single enantiomer in pure form

Which of the following best describes a racemic solid solution?

• A) A heterogeneous mixture of enantiomers
• B) A homogeneous crystalline phase where both enantiomers are randomly distributed
• C) A supercooled racemic liquid
• D) A system that cannot be separated into enantiomers

What type of interaction primarily stabilizes a racemic compound?

• A) Hydrogen bonding and other strong intramolecular interactions between enantiomers
• B) Dipole-dipole interactions
• C) Random distribution of enantiomers in the crystal lattice
• D) π-π stacking interactions

What is the expected optical rotation of a racemic mixture?

• Positive
• Negative
• Zero
• Depends and vary based on solvent