Which of the following molecules is chiral?

• A. ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}$
• B. ${\mathrm{CH}}_3\mathrm{COOH}$
• C. ${\mathrm{CH}}_3\mathrm{CHBrClF}$
• D. ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Cl}$

Answer: (C)

Verified step by step guidance

1. Recall that a molecule is chiral if it has at least one carbon atom bonded to four different substituents, making it a stereocenter (chiral center).
2. Examine each molecule and identify the carbon atoms to check if any carbon is attached to four distinct groups.
3. For \(\mathrm{CH_3CH_2OH}\) (ethanol), the carbons are bonded to hydrogens and other carbons or oxygen, but none have four different groups; thus, it is achiral.
4. For \(\mathrm{CH_3COOH}\) (acetic acid), the carbons are bonded to hydrogens, oxygens, and carbons, but again no carbon has four different substituents, so it is achiral.
5. For \(\mathrm{CH_3CHBrClF}\), the second carbon is bonded to a hydrogen, bromine, chlorine, and fluorine — four different substituents — making this carbon a chiral center and the molecule chiral.