Answer: K3[Fe(CN) 6 ].
- A K3[Fe(CN)<sub>6</sub>]
- B K<sub>4</sub>[Fe(CN)<sub>6</sub>]
- C K[Fe(CN)<sub>6</sub>]
- D K2[Fe(CN)<sub>6</sub>]
Correct answer: A. K3[Fe(CN)<sub>6</sub>]
Explanation: Fe is +3, each CN- is -1, so 6 CN- = -6; total complex charge = +3 - 6 = -3; 3 K+ needed to balance.
The three common coordination geometries: octahedral (6 ligands), tetrahedral (4 ligands), and square planar (4 ligands in one plane).
Concept context
Study of compounds where a central metal atom is bonded to surrounding ligands. Covers nomenclature, types of isomerism, bonding theories (VBT, CFT), and applications in medicine, photography, and industry.