Coordination Compounds · JEE Main previous year questions

1. A.8 and 6
2. B.8 and 8
3. C.6 and 8
4. D.6 and 6

The correct statements among I to III are : (I) Valence bond theory cannot explain the color exhibited by transition metal complexes. (II) Valence bond theory can predict quantitatively the magnetic properties of transition metal complexes. (III) Valence bond theory cannot distinguish ligands as weak and strong field ones.

1. A.(II) and (III) only
2. B.(I) and (II) only
3. C.(I), (II) and (III)
4. D.(I) and (III) only

The metal d-orbitals that are directly facing the ligands in ${\mathrm{K}}_3[\mathrm{Co}(\mathrm{CN}{)}_6]$ are -

1. A.${\mathrm{d}}_{{\mathrm{x}}^2-{\mathrm{y}}^2}$ and ${\mathrm{d}}_{{\mathrm{z}}^2}$
2. B.${\mathrm{d}}_{\mathrm{xy}}$, ${\mathrm{d}}_{\mathrm{xz}}$ and ${\mathrm{d}}_{\mathrm{yz}}$
3. C.${\mathrm{d}}_{\mathrm{xz}}$, ${\mathrm{d}}_{\mathrm{yz}}$ and ${\mathrm{d}}_{{\mathrm{z}}^2}$
4. D.${\mathrm{d}}_{\mathrm{xy}}$ and ${\mathrm{d}}_{{\mathrm{x}}^2-{\mathrm{y}}^2}$

The magnetic moment of an octahedral homoleptic Mn(II) complex is 5.9 BM. The suitable ligand for this complex is -

1. A.$\mathrm{C}{\mathrm{N}}^{-}$
2. B.ethylenediamine
3. C.$\mathrm{NC}{\mathrm{S}}^{-}$
4. D.CO

The number of bridging CO ligand(s) and Co-Co bond(s) in $\mathrm{C}{\mathrm{o}}_2(\mathrm{CO}{)}_8$, respectively are :

1. A.2 and 0
2. B.0 and 2
3. C.4 and 0
4. D.2 and 1

Two complexes $[\mathrm{Cr}({\mathrm{H}}_2\mathrm{O}{)}_6]\mathrm{C}{\mathrm{l}}_3$ (A) and $[\mathrm{Cr}(\mathrm{N}{\mathrm{H}}_3{)}_6]\mathrm{C}{\mathrm{l}}_3$ (B) are violet and yellow coloured, respectively. The incorrect statement regarding them is :

1. A.${\Delta }_0$ values of (A) and (B) are calculated from the energies of violet and yellow light, respectively
2. B.both are paramagnetic with three unpaired electrons
3. C.both absorb energies corresponding to their complementary colors.
4. D.${\Delta }_0$ value for (A) is less than that of (B).

1. A.
2. B.
3. C.
4. D.

Consider the following reaction and statements: $[\text{Co}({\text{NH}}_3{)}_4{\text{Br}}_2{]}^{+}+{\text{Br}}^{-}\to [\text{Co}({\text{NH}}_3{)}_3{\text{Br}}_3]+{\text{NH}}_3$ (I) Two isomers are produced if the reactant complex ion is a cis-isomer (II) Two isomers are produced if the reactant complex ion is a trans-isomer (III) Only one isomer is produced if the reactant complex ion is a trans-isomer (IV) Only one isomer is produced if the reactant complex ion is a cis – isomer The correct statements are

1. A.(II) and (IV)
2. B.(I) and (II)
3. C.(I) and (III)
4. D.(III) and (IV)

The number of geometric isomers that can exist for square planar $[\mathrm{Pt}(\mathrm{Cl})(\mathrm{py})(\mathrm{N}{\mathrm{H}}_3)(\mathrm{N}{\mathrm{H}}_2\mathrm{OH}){]}^{+}$ is (py = pyridine) :

1. A.$3$
2. B.$4$
3. C.$6$
4. D.$2$

The octahedral complex of a metal ion ${\mathrm{M}}^{3+}$ with four monodentate ligands ${\mathrm{L}}_1,{\mathrm{L}}_2,{\mathrm{L}}_3$ and ${\mathrm{L}}_4$ absorb wavelengths in the region of red, green, yellow and blue, respectively. The increasing order of ligand strength of the four ligands is :

1. A.${\mathrm{L}}_3<{\mathrm{L}}_2<{\mathrm{L}}_4<{\mathrm{L}}_1$
2. B.${\mathrm{L}}_1<{\mathrm{L}}_2<{\mathrm{L}}_4<{\mathrm{L}}_3$
3. C.${\mathrm{L}}_4<{\mathrm{L}}_3<{\mathrm{L}}_2<{\mathrm{L}}_1$
4. D.${\mathrm{L}}_1<{\mathrm{L}}_3<{\mathrm{L}}_2<{\mathrm{L}}_4$

The complex ion $[\mathrm{Pt}(\mathrm{N}{\mathrm{O}}_2)(\mathrm{Py})(\mathrm{N}{\mathrm{H}}_3)(\mathrm{N}{\mathrm{H}}_2\mathrm{OH}){]}^{+}$ will give

1. A.2 isomers (Geometrical)
2. B.3 isomers (Geometrical)
3. C.6 isomers (Geometrical)
4. D.4 isomers (Geometrical)

Which of the following complex ions will exhibit optical isomerism? (en = 1,2-diamine ethane).

1. A.$[\mathrm{Cr}(\mathrm{N}{\mathrm{H}}_3{)}_2\mathrm{C}{\mathrm{l}}_2{]}^{+}$
2. B.$[\mathrm{Co}(\mathrm{en}{)}_2\mathrm{C}{\mathrm{l}}_2{]}^{+}$
3. C.$[\mathrm{Co}(\mathrm{N}{\mathrm{H}}_3{)}_4\mathrm{C}{\mathrm{l}}_2{]}^{+}$
4. D.$[\mathrm{Zn}(\mathrm{en}{)}_2{]}^{2+}$

A solution containing 2.675g of $\mathrm{CoC}{\mathrm{l}}_3\cdot 6N{\mathrm{H}}_3$ (molar mass = $267.5\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$) is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of $\mathrm{AgN}{\mathrm{O}}_3$ to give 4.78 g of AgCl (molar mass = $143.5\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$). The formula of the complex is : (At. Mass of Ag = 108 u)

1. A.$[\mathrm{Co}(\mathrm{N}{\mathrm{H}}_3{)}_6]\mathrm{C}{\mathrm{l}}_3$
2. B.$[\mathrm{CoC}{\mathrm{l}}_2(\mathrm{N}{\mathrm{H}}_3{)}_4]\mathrm{Cl}$
3. C.$[\mathrm{CoC}{\mathrm{l}}_3(\mathrm{N}{\mathrm{H}}_3{)}_3]$
4. D.$[\mathrm{CoCl}(\mathrm{N}{\mathrm{H}}_3{)}_5]\mathrm{C}{\mathrm{l}}_2$

Nickel ($Z=28$) combines with a uninegative monodentate ligand ${\mathrm{X}}^{-}$ to form a paramagnetic complex $[\mathrm{Ni}{\mathrm{X}}_4{]}^{2-}$. The number of unpaired electron(s) in the nickel and geometry of this complex ion are, respectively

1. A.one, tetrahedral
2. B.two, tetrahedral
3. C.one, square planar
4. D.two, square planar

The IUPAC name for the complex $[\mathrm{Co}(\mathrm{N}{\mathrm{O}}_2)(\mathrm{N}{\mathrm{H}}_3{)}_5]\mathrm{C}{\mathrm{l}}_2$ is

1. A.nitrito-N-pentaamminecobalt (III) chloride
2. B.nitrito-N-pentaamminecobalt (II) chloride
3. C.pentaammine nitrito-N-cobalt (II) chloride
4. D.pentaammine nitrito-N-cobalt (III) chloride

The IUPAC name of the coordination compound ${\mathrm{K}}_3[\mathrm{Fe}(\mathrm{CN}{)}_6]$ is

1. A.Potassium hexacyanoferrate (II)
2. B.Potassium hexacyanoferrate (III)
3. C.Potassium hexacyanoiron (II)
4. D.Tripotassium hexacyanoiron (II)

The coordination number of central metal atom in a complex is determined by :

1. A.the number of ligands around a metal ion bonded by sigma bonds
2. B.the number of only anionic ligands bonded to the metal ion
3. C.the number of ligands around a metal ion bonded by sigma and pi- bonds both
4. D.the number of ligands around a metal ion bonded by pi-bonds

Coordination compound have great importance in biological systems. In this context which of the following statements is incorrect?

1. A.Chlorophylls are green pigments in plants and contains calcium
2. B.Carboxypeptidase – A is an enzyme and contains zinc
3. C.Cyanocobalamin is ${\mathrm{B}}_{12}$ and contains cobalt
4. D.Haemoglobin is the red pigment of blood and contains iron

Among the properties (a) reducing (b) oxidising (c) complexing, the set of properties shown by $\mathrm{C}{\mathrm{N}}^{-}$ ion towards metal species is :

1. A.c, a
2. B.b, c
3. C.a, b
4. D.a, b, c