What is the IUPAC name of [Co(NH₃)₆]Cl₃ ?

Hexaammine cobalt (III) chloride

The correct answer is option 2. Hexaammine cobalt (III) chloride

The IUPAC naming rules for coordination compounds involve naming the ligands first in alphabetical order, followed by the central metal ion, and finally the oxidation state of the metal in Roman numerals in parentheses. The anion name follows outside the square brackets.

For the complex \([Co(NH_3)_6]Cl_3\):

The ligand \(NH_3\) (ammine) is neutral.

The central metal ion is cobalt.

The oxidation state of cobalt can be determined by considering the charges: the complex ion must balance the 3 negative charges from the chloride ions, so cobalt must have a +3 oxidation state.

Therefore, the IUPAC name for \([Co(NH_3)_6]Cl_3\) is: \(\text{Hexaammine cobalt(III) chloride}\)