(A) [FeO4]2− (B) [Fe(CN)6]3−
(C) [Fe(CN)5NO]2− (D) [CoCl4]2−
(E) [Co(H2O)3F3]
Choose the correct answer from the options given below :
(B) and (D) only
(C) and (E) only
(A), (B) and (D) only
(A), (C) and (E) only
- (A) \([FeO_4]^{2-}\): Iron in this complex is in the +2 oxidation state, with \( d^6 \) electrons. Since 6 is an even number, this complex does not meet the requirement for an odd number of d-electrons.
- (B) \([Fe(CN)_6]^{3-}\): Iron in this complex is in the +3 oxidation state, with \( d^5 \) electrons. This gives an odd number of d-electrons, so this is a homoleptic complex with odd d-electrons.
- (C) \([Fe(CN)_6]^{2-}\): Iron is in the +2 oxidation state with \( d^6 \) electrons. This complex has an even number of d-electrons.
- (D) \([CoCl_4]^{2-}\): Cobalt in this complex is in the +2 oxidation state, with \( d^7 \) electrons. This gives an odd number of d-electrons, so this is a homoleptic complex with odd d-electrons.
- (E) \([Co(H_2O)_6]^{3+}\): Cobalt in the +3 oxidation state has \( d^6 \) electrons, which is an even number.
Thus, the correct answer is (1) (B) and (D) only.
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
| List I (Substances) | List II (Element Present) |
| (A) Ziegler catalyst | (I) Rhodium |
| (B) Blood Pigment | (II) Cobalt |
| (C) Wilkinson catalyst | (III) Iron |
| (D) Vitamin B12 | (IV) Titanium |
| List-I (Complex ion) | List-II (Spin only magnetic moment in B.M.) |
|---|---|
| (A) [Cr(NH$_3$)$_6$]$^{3+}$ | (I) 4.90 |
| (B) [NiCl$_4$]$^{2-}$ | (II) 3.87 |
| (C) [CoF$_6$]$^{3-}$ | (III) 0.0 |
| (D) [Ni(CN)$_4$]$^{2-}$ | (IV) 2.83 |
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,