Which of the following molecules is chiral?

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

Answer: (D)

Verified step by step guidance

1. Identify the concept of chirality: A molecule is chiral if it has a carbon atom bonded to four different substituents, making it a stereocenter (chiral center).
2. Examine each molecule's structure to find any carbon atoms bonded to four distinct groups. For example, look at the first molecule CH3-CH2-OH and check if any carbon has four different groups attached.
3. For the second molecule CH3-CH2-Cl, analyze the carbons similarly to see if any carbon is attached to four different substituents.
4. For the third molecule CH2Cl-CH2Cl, note that both carbons are bonded to similar groups, so check if any carbon has four unique substituents.
5. Finally, consider the molecule CH3-CHBrClF, where the second carbon is bonded to a hydrogen, bromine, chlorine, and fluorine—four different groups—making it chiral.