Match List-I with List-II.
| List-I (Coordination compound) | List-II (Feature of its IUPAC name) |
|---|---|
| (A) \( \ce{K2[Zn(OH)4]} \) | (I) The prefix tris is used for a ligand |
| (B) \( \ce{[NiCl2(PPh3)2]} \) | (II) The ligand ammine is named before the ligand aqua |
| (C) \( \ce{[Co(H2NCH2CH2NH2)3]2(SO4)3} \) | (III) The name of the metal ends with the suffix –ate |
| (D) \( \ce{[Cr(NH3)3(H2O)3]Cl3} \) | (IV) The prefix bis is used for a ligand |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A-III, B-IV, C-I, D-II
In an IUPAC name the ligands are named first, in alphabetical order, with di, tri, etc. for their number; bis, tris, tetrakis are used when the ligand name itself has a numerical prefix.
The metal keeps its own name in a cation or a neutral molecule and ends in –ate in an anion.
(A) \( \ce{K2[Zn(OH)4]} \) — This matches (III). The complex ion \( \ce{[Zn(OH)4]^2-} \) is an anion, so zinc is named zincate: potassium tetrahydroxidozincate(II).
(B) \( \ce{[NiCl2(PPh3)2]} \) — This matches (IV). The ligand name triphenylphosphine already contains the prefix tri, so its number is shown by bis: dichloridobis(triphenylphosphine)nickel(II). The molecule is neutral, so the metal is plain nickel, not nickelate.
(C) \( \ce{[Co(H2NCH2CH2NH2)3]2(SO4)3} \) — This matches (I). The ligand ethane-1,2-diamine has a numerical prefix in its name (di), so three of them are shown by tris: tris(ethane-1,2-diamine)cobalt(III) sulphate.
(D) \( \ce{[Cr(NH3)3(H2O)3]Cl3} \) — This matches (II). Its name is triamminetriaquachromium(III) chloride; by alphabetical order ammine comes before aqua. Here plain tri is used, because ammine and aqua have no numerical prefix of their own.
NCERT (2026-27 edition):
5.3.2 Naming of Mononuclear Coordination Compounds – “…If the complex ion is an anion, the name of the metal ends with the suffix – ate.”
Example 5.2 – “Write the formulas for the following coordination compounds: … (b) potassium tetrahydroxidozincate(II)” … Solution: “(b) K2[Zn(OH)4]”
“When the names of the ligands include a numerical prefix, then the terms, bis, tris, tetrakis are used, the ligand to which they refer being placed in parentheses. For example, [NiCl2(PPh3)2] is named as dichloridobis(triphenylphosphine)nickel(II).”
“2. [Co(H2NCH2CH2NH2)3]2(SO4)3 is named as: tris(ethane-1,2–diamine)cobalt(III) sulphate”
“1. [Cr(NH3)3(H2O)3]Cl3 is named as: triamminetriaquachromium(III) chloride … The amine ligands are named before the aqua ligands according to alphabetical order.”