What is the correct name for the binary molecular compound $P{C}_{\mathrm{l}}5$ (commonly written as $\mathrm{PC}{l}_5$)?

• A. Phosphorus pentachloride
• B. Diphosphorus pentachloride
• C. Phosphorus(V) chloride
• D. Phosphorus chlorate

Answer: (A)

Verified step by step guidance

1. Identify the elements present in the compound. Here, the formula is \(\mathrm{PCl}_5\), which contains phosphorus (P) and chlorine (Cl).
2. Recognize that this is a binary molecular compound, meaning it consists of two nonmetal elements.
3. Use the prefixes to indicate the number of atoms of each element: 'penta-' means 5 chlorine atoms, and since there is only one phosphorus atom, no prefix is needed for phosphorus.
4. Name the first element (phosphorus) as is, and name the second element (chlorine) with the suffix '-ide', changing chlorine to 'chloride'.
5. Combine the names with the appropriate prefix for chlorine to get the correct name: 'Phosphorus pentachloride'.