Question

The total number of pair of enantiomers possible with molecular formula C$_5$H$_{12}$O is ..............

Hint:

A molecule is chiral only if its carbon has four different groups—check each isomer systematically.

Answer 1

Correct Answer: 4

Step 1: Identify all structural isomers of C$_5$H$_{12$O.}
These include pentanols and methylbutanols in various positions.
We look for structures containing exactly one chiral carbon.
Step 2: Check each for chirality.
Chiral alcohols possible:
• 2-pentanol → chiral → 1 pair
• 3-pentanol → chiral → 1 pair
• 2-methyl-1-butanol → chiral → 1 pair
Others are achiral.
But only two of these exist as unique configurational enantiomers respecting identical substituent sets.
Thus, 2 independent chiral centres (in separate molecules).
Step 3: Conclusion.
Hence, total enantiomeric pairs = 2.