Chapter 20

For the complex \(\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}\) (a) Shape is tetrahedral (b) Hybridization state of central ion is \(\mathrm{sp}^{3}\) (c) Effective atomic number of central ion is 35 (d) Number of unpaired electrons present in the central ion is 1

Identify the coordination compounds (a) \(\mathrm{FeSO}_{4} \cdot\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4} \cdot 6 \mathrm{H}_{2} \mathrm{O}\) (b) \(\mathrm{Fe}(\mathrm{CN})_{2} \cdot 4 \mathrm{KCN}\) (c) \(\mathrm{KCl} \cdot \mathrm{MgCl}_{2} .6 \mathrm{H}_{2} \mathrm{O}\) (d) \(\mathrm{CuSO}_{4} .4 \mathrm{NH}_{3}\)

The main draw back of valence bond theory is/are (a) It cannot explain magnetic properties of co-ordination compounds (b) It cannot distinguish between high spin and low spin complex (c) It does not provide an answer to the origin of characteristic colours of complex ions (d) It is a qualitative approach

The coordination compound is a complex substance which contains a central metal atom or ion surrounded by oppositely charged ions or neutral molecules. These compounds exhibit structural as well as stereoisomerism. Hybridisation theory explains the geometry of the complex. Crystal field theory explains the colour of complexes and magnetic properties. Which one of the following does not show optical activity? (a) \(\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right]^{+}\) (b) \(\left[\mathrm{Pt}(\mathrm{Br})(\mathrm{Cl})(\mathrm{I})\left(\mathrm{NO}_{2}\right)\left(\mathrm{C}_{6} \mathrm{H}_{3} \mathrm{~N}\right)\left(\mathrm{NH}_{3}\right)\right]^{-}\) (c) \(\operatorname{Cis}\left[\mathrm{Co}(\mathrm{en})\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right]^{+}\) (d) \(\operatorname{Cis}\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right]^{+}\)

The coordination compound is a complex substance which contains a central metal atom or ion surrounded by oppositely charged ions or neutral molecules. These compounds exhibit structural as well as stereoisomerism. Hybridisation theory explains the geometry of the complex. Crystal field theory explains the colour of complexes and magnetic properties. Identify the correct statement (a) \(\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-}\) is tetrahedral and paramagnetic (b) \(\left[\mathrm{NiCl}_{4}\right]^{2-}\) is square planar and paramagnetic (c) \(\left[\mathrm{Ni}(\mathrm{CO})_{4}\right]\) is square planar and paramagnetic (d) \(\left[\mathrm{Cu}(\mathrm{CN})_{4}\right]^{3-}\) is tetrahedral and diamagnetic

When degenerate d-orbitals of an isolated atom/ion are brought under the impact of magnetic field of ligands, the degeneracy is lost. The two newly formed sets of d-orbitals, depending upon nature and magnetic field of ligands are either stabilized or destabilized. The energy difference between the two sets whenever lies in the visible region of the electromagnetic spectrum, then the electronic transition \(\mathrm{t}_{2 \mathrm{~g}} \rightleftharpoons \mathrm{e}_{\mathrm{g}}\) are responsible for colours of the co-ordination compounds Which of the following colour is not due to d-d transition of (a) Yellow colour of CdS. (b) Red colour of blood (c) Orange colour of \(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}\) in acidic medium. (d) Both (a) and (c).

When degenerate d-orbitals of an isolated atom/ion are brought under the impact of magnetic field of ligands, the degeneracy is lost. The two newly formed sets of d-orbitals, depending upon nature and magnetic field of ligands are either stabilized or destabilized. The energy difference between the two sets whenever lies in the visible region of the electromagnetic spectrum, then the electronic transition \(\mathrm{t}_{2 \mathrm{~g}} \rightleftharpoons \mathrm{e}_{\mathrm{g}}\) are responsible for colours of the co-ordination compounds Which of following complex ions will be coloured in aqueous state? (a) \(\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-}\) (b) \(\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}\) (c) \(\left[\mathrm{Sc}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}\) (d) Both (b) and (c)

$$ \begin{aligned} &\begin{array}{ll} \text { Match the following } \\ \hline \text { Column-I } & \text { Column-II } \\ \hline \begin{array}{ll} \text { (a) }\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+} & \text { (p) } \mathrm{d}^{2} \mathrm{sp}^{3} \\ \text { (b) }\left[\mathrm{Cu}(\mathrm{CN})_{4}\right]^{3-} & \text { (q) } \mathrm{sp}^{3} \\ \text { (c) }\left[\mathrm{Co}\left(\mathrm{NO}_{2}\right)_{6}\right]^{3-} & \text { (r) Number of unpaired } \\ &\text { electrons is zero } \end{array} \\ \text { (d) }\left[\mathrm{FeCl}_{4}\right]^{-} \text {(s) Paramagnetic } \\ & \text { (t) Diamangetic } \\ \hline \end{array} \end{aligned} $$

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \hline \text { Column-I } & \text { Column-II } \\ \hline \text { (a) }\left[\mathrm{Co}\left(\mathrm{NO}_{2}\right)_{2}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\left(\mathrm{NH}_{3}\right)_{2}\right] & \text { (p) } \text { Number of } \\ \mathrm{NO}_{3} & \text { stereoisomers } \\ & =6 \\ \text { (b) }\left[\mathrm{Ni}(\mathrm{en})_{3}\right] \mathrm{Br}_{3} & \text { (q) } \begin{array}{l} \text { Linkage } \\ \text { isomerism } \end{array} \\ \text { (c) }\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{3}(\mathrm{py})_{3}\right] \mathrm{Br}_{2} & \text { (r) } \begin{array}{l} \text { Ionization } \\ \text { isomerism } \end{array} \\ \text { (d) }\left[\mathrm{Pt}(\mathrm{en})(\mathrm{SCN})_{2}\right]\left(\mathrm{NO}_{3}\right)_{2} & \text { (s) } \begin{array}{l} \text { Optical } \\ \text { isomerism } \end{array} \\ & \text { (t) } \text { Geometrical } \\ & \text { isomerism } \\ \hline \end{array} \end{aligned} $$

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \hline \text { Column-I (Inorganic ions) } & \begin{array}{l} \text { Column-II (can } \\ \text { get tested using } \\ \text { reagent) } \end{array} \\ \hline \text { (a) } \mathrm{Co}^{2+} & \text { (p) } \mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right] \\ \text { (b) } \mathrm{Cu}^{2+} & \text { (q) } \mathrm{KSCN} \\ \text { (c) } \mathrm{Fe}^{3+} & \text { (r) } \mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right] \\ \text { (d) } \mathrm{Zn}^{2+} & \text { (s) } \mathrm{KNO}_{2}+ \\ & \mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H} \\ & \text { (t) } \mathrm{K}_{2}\left[\mathrm{Hg}(\mathrm{SCN})_{4}\right] \\ \hline \end{array} \end{aligned} $$

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \hline \text { Column-I } & \text { Column-II } \\ \hline \text { (a) }\left[\mathrm{MnCl}_{6}\right]^{3-} & \text { (p) One unpaired electron } \\ \text { (b) }\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-} & \text { (q) } \mathrm{d}^{2} \mathrm{sp}^{3} \\ \text { (c) }\left[\mathrm{CoF}_{6}\right]^{3-} & \text { (r) } \mathrm{sp}^{3} \mathrm{~d}^{2} \\ \text { (d) }\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2-} & \text { (s) Four unpaired electrons } \\ & \text { (t) Three unpaired electrons } \\ \hline \end{array} \end{aligned} $$

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \hline \text { Column-I } & \text { Column-II } \\ \hline \text { (a) }\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\right] & \text { (p) Geometrical isomers } \\ \mathrm{Cl}_{2} & \\ \text { (b) }\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right] & \text { (q) Paramagnetic } \\ \text { (c) }\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5} \mathrm{Cl}\right] \mathrm{Cl} & \text { (r) Diamagnetic } \\ \text { (d) }\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{Cl}_{2} & \text { (s) } \begin{array}{l} \text { Metal ion with }+2 \\ \text { oxidation state } \end{array} \\ & \text { (t) } s p^{3} \mathrm{~d}^{2} \text { hybridization } \\ & \text { of central metal atom } \end{array} \end{aligned} $$

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \hline \text { Column-I } & \text { Column-II } \\ \hline \text { (a) }\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-} & \text { (p) Octahedral } \\ \text { (b) }\left[\mathrm{MnF}_{6}\right]^{4-} & \text { (q) Paramagnetic } \\\ \text { (c) }\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-} & \text { (r) Square planar } \\ \text { (d) }\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+} & \text { (s) } \mathrm{d}^{2} \mathrm{sp}^{3} \text { hybridization } \\ & \text { (t) Weak field ligand. } \\ \hline \end{array} \end{aligned} $$

$$ \begin{aligned} &\text { Match the following }\\\ &20\\\ &\begin{array}{ll} \hline \text { Column-I } & \text { Column-II } \\ \hline \text { (a) } \mathrm{Na}_{2}\left[\mathrm{Pt}(\mathrm{SCN})_{4}\right] & \text { (p) Ionisation } \\ \text { (b) }\left[\mathrm{CrCl}_{2}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{NO}_{3} & \text { (q) Linkage isomerism } \\ \text { (c) }\left[\mathrm{Pt}\left(\mathrm{NO}_{2}\right)(\mathrm{gly})\right. & \text { (r) Geometrical } \\ \left.\left(\mathrm{NH}_{3}\right)\right] & \text { isomerism } \\ \text { (d) } \mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{OH})_{2}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{2}\right] & \text { (s) optical isomerism } \\ & \text { (t) hydrate isomerism } \\ \hline \end{array} \end{aligned} $$

The mineral (A) is \(\left[\mathrm{CuCl}_{2} \cdot \mathrm{xCu}(\mathrm{OH})_{2}\right]\). A \(45.05 \mathrm{ml}\) solution of \(0.5089 \mathrm{M}\) HCl was required to react completely with \(1.6320 \mathrm{~g}\) of the compound (A) whose molar mass is 427 . Hence, \(x\) is

14..How many milliliters of \(0.05 \mathrm{M} \mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]\) solution are required for titration of \(60 \mathrm{ml}\) of \(0.01\) M \(\mathrm{ZnSO}_{4}\) solution, when the product of reaction is \(\mathrm{K}_{2} \mathrm{Zn}_{3}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]_{2} ?\)

For the coordination compound \(\mathrm{PtCl}_{4} \cdot 5 \mathrm{NH}_{3}\), the charge on cation is found to be \(+3\). How many ions are furnished on ionization of the complex?

\(\mathrm{Na}_{2} \mathrm{O}\) has antifluorite structure. The coordination number of oxide ion is

The number of geomatrical isomers exhibited by \(\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}_{3}\) is

Amongst the following, the total number of species which are diamagnetic is \(\mathrm{K}_{4}[\mathrm{Fe}(\mathrm{CN})], \mathrm{K}_{3}\left[\mathrm{Cr}(\mathrm{CN})_{6}\right], \mathrm{K}_{3}[\mathrm{Co}(\mathrm{CN})]\) \(\mathrm{K}_{2}\left[\mathrm{Ni}(\mathrm{CN})_{4}\right],\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}, \mathrm{K}_{2} \mathrm{TiF}_{6}\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}\)

The possible number of co-ordination isomers of \(\mathrm{Pt}(\mathrm{Py})_{4} \mathrm{CuCl}_{4}\) are

When excess of \(\mathrm{KCN}\) is added to aqueous solution of copper sulphate a co-ordination compound \(\mathrm{K}_{\mathrm{x}}\left[\mathrm{Cu}(\mathrm{CN})_{4}\right]\) is formed. The value of \(\mathrm{x}\) is

The number of viable coordination isomers possible for the complex \(\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{4}\right]\left[\mathrm{CuCl}_{4}\right]\) should be ?

In \(\left[\mathrm{Cr}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{3-}\), the isomerism shown is [2002] (a) optical (b) ionization (c) geometrical (d) ligand

In the complexes \(\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+},\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}, \quad[\mathbf{2 0 0 2}]\) \(\left[\mathrm{Fe}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{3-}\) and \([\mathrm{FeCl}]^{3}\), more stability is shown by (a) \(\left[\mathrm{FeCl}_{6}\right]^{3-}\) (b) \(\left[\mathrm{Fe}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{3-}\) (c) \(\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}\) (d) \(\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}\)

A similarity between optical and geometrical isomerism is that (a) if in a compound one is present then the other will also be present (b) each gives equal number of isomers for a given compound (c) both are included in stereo isomerism (d) they have no similarity

A square planar complex is formed by hybridization of which atomic orbitals? (a) \(s, p x, p y, d x^{2}-y^{2}\) (b) s, px, py, dyz (c) s, px, py, dz \(^{2}\) (d) s, px, py, dxy

The type of isomerism present in nitropentaamine chromium (III) chloride is (a) ionization (b) optical (c) polymerization (d) linkage

In the coordination compound \(\left.\mathrm{K}_{4} \mathrm{Ni}(\mathrm{CN})_{4}\right]\), the oxidation state of nickel is (a) \(-1\) (b) 0 (c) \(+1\) (d) \(+2\)

A mole of complex compound \(\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}_{3}\) gives 3 mole of ions, when dissolved in water. One mole of the same complex reacts with two mole of \(\mathrm{AgNO}_{3}\) solution to form two mole of \(\mathrm{AgCl}(\mathrm{s})\). The structure of the complex is (a) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}_{3}\right] .2 \mathrm{NH}_{3}\) (b) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right] \cdot \mathrm{Cl}_{2}\) (c) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl} .2 \mathrm{NH}_{3}\) (d) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl}_{2} .2 \mathrm{NH}_{3}\)

Coordination compounds have great importance in biological systems. In this context, which of the following statements is incorrect? (a) chlorophylls are green pigments in plants and contain calcium (b) haemoglobin is the red pigment of blood and contains iron (c) cyanocobalamin is vitamin \(\mathrm{B}_{12}\) and contains cobalt (d) carboxypeptidase-A is an enzyme and contains zinc

Which one of the following has largest number of isomers? (a) \(\left[\mathrm{Ru}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right]^{+}\) (b) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right]^{2+}\) (c) \(\left[\mathrm{Ir}\left(\mathrm{PR}_{3}\right)_{2} \mathrm{H}(\mathrm{CO})\right]^{2+}\) (d) \(\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right]^{+}\) \([\mathrm{R}=\) alkyl group, en \(=\) ethylenediamine \(]\)

The correct order of magnetic moments (spin only values in B.M.) among the following is (Atomic number of \(\mathrm{Mn}=25, \mathrm{Fe}=26, \mathrm{Co}=27\) ) (a) \(\left[\mathrm{MnCl}_{4}\right]^{2-}>\left[\mathrm{CoCl}_{4}\right]^{2-}>\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4}\) (b) \(\left[\mathrm{MnCl}_{4}\right]^{2-}>\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4}>\left[\mathrm{CoCl}_{4}\right]^{2-}\) (c) \(\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4}>\left[\mathrm{MnCl}_{4}\right]^{2->}\left[\mathrm{CoCl}_{4}\right]^{2-}\) (d) \(\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4}>\left[\mathrm{CoCl}_{4}\right]^{2-}>\left[\mathrm{MnCl}_{4}\right]^{2-}\)

The coordination number of a central metal atom in a complex is determined by (a) the number of only anionic ligands bonded to the metal ion (b) the number of ligands around a metal ion bonded pi-bonds (c) the number of ligands around a metal ion bonded by sigma and pi-bonds (d) the number of ligands around a metal ion bonded by sigma bonds

The oxidation state of \(\mathrm{Cr}\) in \(\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right]^{+} \quad[\mathbf{2 0 0 5}]\) (a) 0 (b) \(+1\) (c) \(+2\) (d) \(+3\)

The IUPAC name of the coordination compound \(\mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]\) is (a) potassium hexacyanoferrate (II) (b) potassium hexacyanoferrate (III) (c) potassium hexacyanoiron (II) (d) ripotassium acyanoiron (II)

Which of the following compounds shows optical isomerism? (a) \(\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}\) (b) \(\left[\mathrm{ZnCl}_{4}\right]^{2}\) (c) \(\left[\mathrm{Cr}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{3}-\) (d) \(\left[\mathrm{Co}(\mathrm{CN})_{6}\right]^{3}-\)

Which one of the following cyano complexes would exhibit the lowest value of paramagnetic behaviour? (a) \(\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-}\) (b) \(\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{3-}\) (c) \([\mathrm{Fe}(\mathrm{CN})]^{3-}\) (d) \(\left[\mathrm{Co}(\mathrm{CN})_{6}\right]^{3-}\)

The value of 'spin only' magnetic moment for one of the following configurations is \(2.84 \mathrm{BM}\). The correct one is (a) \(\mathrm{d}^{4}\) (in strong ligand field) (b) \(\mathrm{d}^{4}\) (in weak ligand field) (c) \(\mathrm{d}^{3}\) (in weak as well as in strong fields) (d) \(\mathrm{d}^{5}\) (in strong ligand field)

The IUPAC name for the complex \(\left[\mathrm{Co}\left(\mathrm{NO}_{2}\right)\left(\mathrm{NH}_{3}\right)_{5}\right]\) \(\mathrm{Cl}_{2}\) is [2006] (a) nitrite-N-pentaamminecobalt(III) chloride (b) nitrite-N-pentaamminecobalt(II) chloride (c) pentaamminonitrite-N-cobalt(II) chloride (d) pentaamminonitrite-N-cobalt(III) chloride

Nickel \((\mathrm{Z}=28)\) combines with a uninegative monodentate ligand \(\mathrm{X}\) - to form a paramagnetic complex \(\left[\mathrm{NiX}_{4}\right]^{2}\), the number of unpaired electrons in nickel and the geometry of this complex ion is (a) one, tetrahedral (b) two, tetrahedral (c) one, square planar (d) two, square planar

In \(\mathrm{Fe}(\mathrm{CO})_{5}\), the Fe-C bond possesses \([\mathbf{2 0 0 6}]\) (a) \(\pi\)-character only (b) both \(\sigma\) and \(\pi\) characters (c) ionic character (d) \(\sigma\) character only

How many EDTA (ethylenediamine-tetraacetic acid) molecules are required to make an octahedral complex with a \(\mathrm{Ca}^{2+}\) ion? [2006] (a) \(\operatorname{six}\) (b) three (c) one (d) two

The 'spin-only' magnetic moment [in units of Bohr magneton \(\left.\left(\mu_{\mathrm{B}}\right)\right]\) of \(\mathrm{Ni}^{2+}\) in aqueous solution would be (Atomic number of \(\mathrm{Ni}=28\) ) [2006] (a) \(2.84\) (b) \(4.90\) (c) 0 (d) \(1.73\)

Which one of the following has a square planar geometry? [2007] (a) \(\left[\mathrm{FeCl}_{4}\right]^{2}\) (b) \(\left[\mathrm{NiCl}_{4}\right]^{2}\) (c) \(\left[\mathrm{PtCl}_{4}\right]^{2-}\) (d) \(\left[\mathrm{CoCl}_{4}\right]^{2-}\)

The coordination number and the oxidation state of the element ' \(\mathrm{E}\) ' in the complex \(\left[\mathrm{E}(\mathrm{en})_{2}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)\right] \mathrm{NO}_{2}\) (Here (en) is ethylene diamine) are, respectively, \([\mathbf{2 0 0 8}]\) (a) 6 and 2 (b) 4 and 2 (c) 4 and 3 (d) 6 and 3

In which of the following octahedral complexes of Co (Atomic number 27), will the magnitude of \(\Delta\). be the highest? [2008] (a) \(\left[\mathrm{Co}(\mathrm{CN})_{6}\right]^{3-}\) (b) \(\left[\mathrm{Co}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{3-}\) (c) \(\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}\) (d) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}\)

Which of the following has an optical isomer? [2009] (a) \(\left[\mathrm{CO}(\mathrm{en})\left(\mathrm{NH}_{3}\right)_{2}\right]^{2+}\) (b) \(\left[\mathrm{CO}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4}(\mathrm{en})\right]^{3+}\) (c) \(\left[\mathrm{CO}(\mathrm{en})_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]^{3+}\) (d) \(\left[\mathrm{CO}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}\right]^{+}\)

Which of the following pairs represents linkage isomers? (a) \(\left[\mathrm{Pd}\left(\mathrm{P} \mathrm{Ph}_{3}\right)_{2}(\mathrm{NCS})_{2}\right]\) and \(\left[\mathrm{Pd}\left(\mathrm{P} \mathrm{Ph}_{3}\right)_{2}(\mathrm{SCN})_{2}\right]\) (b) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{NO}_{3}\right] \mathrm{SO}_{4}\) and \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{SO}_{4}\right] \mathrm{NO}_{3}\) (c) \(\left[\mathrm{Pt} \mathrm{Cl}_{2}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Br}_{2}\) and (d) \(\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]\left[\mathrm{Pt} \mathrm{Cl}_{4}\right]\) and \(\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{4}\right]\left[\mathrm{CuCl}_{4}\right]\)

Which one of the following has an optical isomer? [2010] (a) \(\left[\mathrm{Zn}(\mathrm{en})\left(\mathrm{NH}_{3}\right)_{2}\right]^{2+}\) (b) \(\left[\mathrm{Co}(\mathrm{en})_{3}\right]^{3+}\) (c) \(\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4}(\mathrm{en})\right]^{3+}\) (d) \(\left[\mathrm{Zn}(\mathrm{en})_{2}\right]^{2+}\) \((\mathrm{en}=\) ethylenediamine \()\)