Which of the following compounds is chiral?

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

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the concept of chirality. A molecule is chiral if it has at least one carbon atom bonded to four different groups, making it a stereocenter (chiral center). This carbon lacks a plane of symmetry, resulting in non-superimposable mirror images (enantiomers).
2. Step 2: Analyze each compound to identify if it contains a carbon with four different substituents. For example, look at the carbon atoms in each molecule and list the groups attached to them.
3. Step 3: For the compound \( \mathrm{CH_3COOH} \) (acetic acid), check the carbons: the methyl carbon is bonded to three hydrogens and one carbonyl carbon, so it does not have four different groups. The carboxyl carbon is double bonded to oxygen and bonded to hydroxyl and methyl groups, so it is not a chiral center.
4. Step 4: For the compound \( \mathrm{CH_3CHBrClF} \), focus on the second carbon (the one bonded to Br, Cl, F, and CH3). Since it is bonded to four different groups (bromine, chlorine, fluorine, and methyl), this carbon is a chiral center, making the molecule chiral.
5. Step 5: For the compounds \( \mathrm{CH_3CH_2Cl} \) and \( \mathrm{CH_3CH_2OH} \), examine the carbons: the second carbon is bonded to two hydrogens, a methyl group, and either Cl or OH, so it does not have four different groups and is not chiral.