Match List-I with List-II.
| List-I (Species) | List-II (Oxidation state of the metal) |
|---|---|
| (A) \( \ce{VO^2+} \) | (I) +6 |
| (B) \( \ce{VO2^+} \) | (II) +4 |
| (C) \( \ce{FeO4^2-} \) | (III) +7 |
| (D) \( \ce{MnO3F} \) | (IV) +5 |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A-II, B-IV, C-I, D-III
The oxidation state of the metal comes from the charge balance: the oxidation states of all the atoms add up to the charge on the species, with O = −2 and F = −1. Oxygen (as oxide and oxocations) and fluorine stabilise high oxidation states of the 3d metals.
(A) \( \ce{VO^2+} \) — This matches (II) +4. x + (−2) = +2, so x = +4. This oxocation stabilises vanadium(IV).
(B) \( \ce{VO2^+} \) — This matches (IV) +5. x + 2(−2) = +1, so x = +5. With one more oxygen than VO2+, this oxocation stabilises vanadium(V).
(C) \( \ce{FeO4^2-} \) — This matches (I) +6. x + 4(−2) = −2, so x = +6. This is the ferrate(VI) ion, formed in alkaline media; it readily decomposes to Fe2O3 and O2.
(D) \( \ce{MnO3F} \) — This matches (III) +7. x + 3(−2) + (−1) = 0, so x = +7. Manganese(VII) is not found in any simple halide, but this oxofluoride is known.
NCERT (2026-27 edition):
4.3.7 Trends in Stability of Higher Oxidation States – “…The +7 state for Mn is not represented in simple halides but MnO3F is known, and beyond Mn no metal has a trihalide except FeX3 and CoF3.”
“…Beyond Group 7, no higher oxides of Fe above Fe2O3, are known, although ferrates (VI)(FeO4)2–, are formed in alkaline media but they readily decompose to Fe2O3 and O2. Besides the oxides, oxocations stabilise VV as VO2+, VIV as VO2+ and TiIV as TiO2+.”