Final answer:
The name of the compound PI₃ is phosphorus triiodide, following the standard chemical naming conventions for binary compounds.The correct option is b.
Step-by-step explanation:
The correct name for the compound PI₃ is phosphorus triiodide. This naming follows the convention where the first part of the compound's name comes from the nonmetal element, phosphorus, and the second part reflects both the halogen with its prefix indicating the number of atoms and the suffix '-ide' indicating that it's a binary compound. In this case, 'tri' stands for three iodine atoms combined with the single phosphorus atom, hence the name phosphorus triiodide.