From the magnetic behaviour of \([NiCl_4]^{2-}\) (paramagnetic) and [Ni\((CO)_4\)] (diamagnetic), choose the correct geometry and oxidation state.
\([NiCl_4]^2-\) : Ni²⁺, square planar [Ni\((CO)_4\)] : Ni(0), square planar
\([NiCl_4]^2-\) : Ni²⁺, tetrahedral [Ni\((CO)_4\)] : Ni(0), tetrahedral
\([NiCl_4]^2-\): Ni²⁺, tetrahedral [Ni\((CO)_4\)] : \(Ni^{2+}\), square planar
\([NiCl_4]^2-\) : Ni(0), tetrahedral [Ni\((CO)_4\)] : Ni(0), square planar
The solution involves determining the geometry and oxidation state of nickel in two complexes: \([NiCl_4]^{2-}\) and \([Ni(CO)_4]\).
1. Analyze \([NiCl_4]^{2-}\):
Nickel in \([NiCl_4]^{2-}\) is in the +2 oxidation state (Ni²⁺). The chloride ions, Cl⁻, are weak field ligands and do not cause pairing of electrons in the d-orbitals of nickel. Thus, the configuration remains high-spin, resulting in unpaired electrons, making it paramagnetic. The paramagnetic property suggests a tetrahedral geometry, as this structure does not allow for complete electron pairing like in square planar complexes.
2. Check \([Ni(CO)_4]\):
In \([Ni(CO)_4]\), nickel remains in the zero oxidation state (Ni(0)). Carbon monoxide, CO, is a strong field ligand, leading to the pairing of electrons in the d-orbitals, thus making the complex diamagnetic. The electron pairing results in no unpaired electrons. In this case, since the complex is diamagnetic and the hybridization involved is sp³, the geometry is tetrahedral.
Conclusion:
| Complex | Oxidation State | Geometry |
|---|---|---|
| \([NiCl_4]^{2-}\) | Ni²⁺ | Tetrahedral |
| \([Ni(CO)_4]\) | Ni(0) | Tetrahedral |
Thus, the correct configuration for the complexes according to the magnetic properties is: \([NiCl_4]^{2-}\): Ni²⁺, tetrahedral; \([Ni(CO)_4]\): Ni(0), tetrahedral.
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,