Which of the following represents PCl5?

The correct representation for PCl5 is phosphorus pentachloride. In chemical nomenclature, the prefixes used in front of the element names indicate the number of atoms of each element present in the molecule. "P" stands for phosphorus, and "Cl" stands for chlorine. The numerical prefix "penta-" signifies that there are five chlorine atoms bonded to one phosphorus atom.

When naming molecular compounds, it is essential to accurately reflect the number of each type of atom present. In this case, since there are five chlorine atoms attached to a single phosphorus atom, the name phosphorus pentachloride correctly identifies the compound. Understanding these prefixes is key for clear communication in chemistry regarding the composition of compounds.

The other names listed do not accurately describe PCl5 due to incorrect prefixes or numbers of chlorine atoms, highlighting the importance of the correct use of nomenclature in chemistry.