Match List-I (complex) with List-II (IUPAC name).
| List-I | List-II |
| (A) [Ni(CO)4] | (p) Tetrachloridoferrate(II) |
| (B) [Ni(CN)4]2− | (q) Tetraamminecopper(II) |
| (C) [Cu(NH3)4]2+ | (r) Tetracyanidonickelate(II) |
| (D) [FeCl4]2− | (s) Tetracarbonylnickel(0) |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A-s, B-r, C-q, D-p
In the IUPAC name the ligands come first (ammine for NH3, carbonyl for CO, anionic ligands ending in –ido), then the metal with its oxidation state in Roman numerals. In a complex anion the metal name ends in –ate.
(A) \( \ce{[Ni(CO)4]} \) — This matches (s) Tetracarbonylnickel(0). CO is neutral, so x + 4(0) = 0 and x = 0; the complex is neutral, so the metal keeps its own name, nickel.
(B) \( \ce{[Ni(CN)4]^2-} \) — This matches (r) Tetracyanidonickelate(II). x + 4(−1) = −2, so x = +2; the complex is an anion, so nickel becomes nickelate.
(C) \( \ce{[Cu(NH3)4]^2+} \) — This matches (q) Tetraamminecopper(II). NH3 is neutral, so x = +2; the complex is a cation, so the metal is named copper.
(D) \( \ce{[FeCl4]^2-} \) — This matches (p) Tetrachloridoferrate(II). x + 4(−1) = −2, so x = +2; in an anion the Latin name ferrate is used for iron.
NCERT (2026-27 edition):
5.3.2 Naming of Mononuclear Coordination Compounds – “(iii) Names of the anionic ligands end in –o, those of neutral and cationic ligands are the same except aqua for H2O, ammine for NH3, carbonyl for CO and nitrosyl for NO.”
“Note: The 2004 IUPAC draft recommends that anionic ligands will end with –ido so that chloro would become chlorido, etc.”
“(v) Oxidation state of the metal in cation, anion or neutral coordination entity is indicated by Roman numeral in parenthesis.”
“(vi) If the complex ion is a cation, the metal is named same as the element. … If the complex ion is an anion, the name of the metal ends with the suffix – ate. … For some metals, the Latin names are used in the complex anions, e.g., ferrate for Fe.”
“(vii) The neutral complex molecule is named similar to that of the complex cation.”