The IUPAC name for \(K[SbCl_5C_6H_5]\) is

potassium pentachloro (phenyl) antimonate (V)

The correct answer is option 2. potassium pentachloro (phenyl) antimonate (V).

Let us first calculate the oxidation number of the central metal ion, i.e.,  antimony.

Here the ligands are chloride and phenyl both of which are monodentate ligands.

Let us consider the oxidation number of \(Sb\) be \(x\)

\(∴ 1 + x + 5(-1) + (-1) =0\)

\(⇒ x -5 = 0\)

\(⇒ x = 5\)

As the complex is an anionic complex s the name of the central metal ion ends with \(-ate\)

Hence the name of the complex is : \(\text{Potassium pentachloro(phenyl) antimonate(V)}\)

The other options are incorrect. Option (1), luteroantimonate (V), is incorrect because the ligand is not called "lutero". Option (3), potassium phenylchloroantimonate (V), is incorrect because the ligand name should be preceded by the prefix "pentachloro". Option (4), potassium benzalantimony (III) chloride, is incorrect because the oxidation state of antimony is +5, not +3.