Which functional group is responsible for the ability to taste phenylthiocarbamide ($\mathrm{PTC}$)?

• A. $\mathrm{Thiourea}$
• B. $\mathrm{Amino}$
• C. $\mathrm{Thiol}$
• D. $\mathrm{Phenyl}$

Answer: (A)

Verified step by step guidance

1. Identify the structure of phenylthiocarbamide (PTC) to understand its functional groups.
2. Recognize that PTC contains a thiourea group, which is characterized by the presence of a sulfur atom double-bonded to a carbon atom that is also bonded to a nitrogen atom.
3. Understand that the thiourea group is responsible for the bitter taste of PTC, as it interacts with taste receptors on the tongue.
4. Differentiate between the functional groups listed: amino, thiol, and phenyl, and note that none of these are responsible for the taste of PTC.
5. Conclude that the thiourea group is the correct functional group responsible for the ability to taste PTC.