Which of the following is the correct name for the molecule PCl_3?

• A. Phosphorus chloride
• B. Phosphorus(III) chloride
• C. Phosphoric trichloride
• D. Phosphorus trichloride

Answer: (D)

Verified step by step guidance

1. Identify the central atom and the attached atoms in the molecule PCl_3. Here, phosphorus (P) is the central atom bonded to three chlorine (Cl) atoms.
2. Determine the type of compound. Since PCl_3 is a binary molecular compound composed of two nonmetals, it follows the naming conventions for covalent compounds.
3. Use prefixes to indicate the number of atoms of each element. The prefix 'tri-' is used for three chlorine atoms, so 'trichloride' is appropriate.
4. Name the central atom first without a prefix (unless there is more than one atom, which is rare for central atoms in such compounds). So, 'phosphorus' is used without a prefix.
5. Combine the parts to form the correct name: 'phosphorus trichloride'. This name correctly reflects the molecular composition and follows IUPAC naming rules for covalent compounds.