Which of the following statements is incorrect?

Options

A. In `K_(3)[Fe(CN)_(6)]`, the ligand has satisfied only the secondary valency of ferreion
B. In `K[Fe(CN)_(6)]`, the ligand has satisfied both primary and secondary valencies of ferric ion.
C. In `K[Fe(CN)_(6)]`, the ligand has satisfied both primary and secondary valencies of ferrous ion
D. In `[Cu(NH_(3))]SO_(4)` the ligand has satisfied only the secondary valency of copper.

Answer

A

Explanation

Primary valency corresponds to the oxidation state of the central metal and secondary valency represents the coordination number of the metal A negative ion when present in the coordination sphere shows a dual behaviour.