The spin-only magnetic moment value of an octahedral complex among \(CoCl_3⋅4NH_3\), \(NiCl_2⋅6H_2O\) and \(PtCl_4⋅2HCl\), which upon reaction with excess of \(AgNO_3\) gives 2 moles of \(AgCl\) is _____ B.M. (Nearest Integer)
Correct Answer: 3
Solution and Explanation
\(CoCl_3⋅4NH_3 \xrightarrow{\text {excess} \ AgNO_3 } [Co(NH_3)_4⋅Cl_2]+AgCl\)
\(NiCl_2⋅6H_2O\xrightarrow{\text {excess} \ AgNO_3 }[Ni(H_2O)_6]_2+ +2AgCl\)
\(PtCl_4⋅2HCl→[PtCl_6]^{4−} + \text {No AgCl ppt}\)
\([Ni^{2+}(H_2O)_6]=d^8=t_2g^6 e^2_g=2\) unpaired~electrons
Magnetic moment,
\(=\sqrt {2(2+2)}\)
\(=\sqrt 8\)
\(≈3\)
So, the answer is \(3\).
Top Questions on coordination compounds
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Given below are two statements:
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Statement II: In the set \( [NO_2] \), \( BeH_2 \), \( BF_3 \), \( AlCl_3 \), all the molecules have incomplete octet around the central atom.
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B. The complex is white in colour.
C. The calculated spin-only magnetic moment of the complex is $2.84$ BM.
D. The calculated CFSE (Crystal Field Stabilization Energy) of Ni in this complex is $-0.8\Delta_o$.
E. The geometrical arrangement of ligands in this complex is similar to that in Ni(CO)$_4$.
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(b) [Co(NH₃)₅ NO₂]²⁺ and [Co(NH₃)₅ ONO]²⁺
(c) [Pt(NH₃)₄][PdCl₄] and [Pd(NH₃)₄][PtCl₄]- TN Board - 2026
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Concepts Used:
Coordination Compounds
A coordination compound holds a central metal atom or ion surrounded by various oppositely charged ions or neutral molecules. These molecules or ions are re-bonded to the metal atom or ion by a coordinate bond.
Coordination entity:
A coordination entity composes of a central metal atom or ion bonded to a fixed number of ions or molecules.
Ligands:
A molecule, ion, or group which is bonded to the metal atom or ion in a complex or coordination compound by a coordinate bond is commonly called a ligand. It may be either neutral, positively, or negatively charged.