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NEET • CHEMISTRY • CO-ORDINATION COMPOUNDS

Co-ordination compounds practice · Medium

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1 Medium
Understanding +4 | -1
The complexes [PtCl2(NH3)4]Br2  and  [PtBr2(NH3)4]Cl2  \left[ {\mathrm{PtC}{\mathrm{l}_2}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]\mathrm{B}{\mathrm{r}_2}\mathrm{\;and\;}\left[ {\mathrm{PtB}{\mathrm{r}_2}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]\mathrm{C}{\mathrm{l}_2}\mathrm{\;} are example for isomerism
View answer and explanation
Correct option: C
Ionization
Option C (Ionization) is correct because the complexes differ in the ions present outside the coordination sphere.
Solution approach
  1. Correct Answer + Core Reason: Ionization. The complexes exchange ions between the coordination sphere and the counter ions.

    Step-by-Step Solution:

    Step 1: Identify the complexes: [PtCl2(NH3)4]Br2  and  [PtBr2(NH3)4]Cl2  \left[ {\mathrm{PtC}{\mathrm{l}_2}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]\mathrm{B}{\mathrm{r}_2}\mathrm{\;and\;}\left[ {\mathrm{PtB}{\mathrm{r}_2}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]\mathrm{C}{\mathrm{l}_2}\mathrm{\;}

    Step 2: Determine the ions present in solution when each complex is dissolved in water.\nComplex 1: [PtCl2(NH3)4]2++2Br−\left[ {\mathrm{PtC}{\mathrm{l}_2}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]^{2+} + 2\mathrm{B}{\mathrm{r}^ - }\nComplex 2: [PtBr2(NH3)4]2++2Cl−\left[ {\mathrm{PtB}{\mathrm{r}_2}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]^{2+} + 2\mathrm{C}{\mathrm{l}^ - }

    Step 3: Observe that the complexes have exchanged ions (Br−\mathrm{Br}^- and Cl−\mathrm{Cl}^-) between the coordination sphere and the counter ions.

    Step 4: Conclude that this is ionization isomerism.

    Why other options are wrong:
    - Option A (Geometrical): Geometrical isomers have the same ligands but different spatial arrangements. These complexes differ in the ions inside and outside the coordination sphere, not just their arrangement.
    - Option B (Optical): Optical isomers are non-superimposable mirror images. These complexes are not chiral.
    - Option D (Linkage): Linkage isomers involve ambidentate ligands that can bind through different atoms. These complexes do not have ambidentate ligands.

    Key Concepts:
    - Isomerism in coordination compounds
    - Ionization isomerism

    Memory Aids:
    - Ionization isomers: Exchange of ions between the coordination sphere and the counter ions.

    Quick Tips:
    - Identify the ions inside and outside the coordination sphere to determine if ionization isomerism is present.
2 Medium
Application +4 | -1
The value of xx on the [Ni(CN)4]x{\left[ {\mathrm{Ni}{{\left( {\mathrm{CN}} \right)}_4}} \right]^x} is:
View answer and explanation
Correct option: B
-2
The correct answer is -2 because the overall charge of the complex ion [Ni(CN)4]x{\left[ {\mathrm{Ni}{{\left( {\mathrm{CN}} \right)}_4}} \right]^x} is -2.
Solution approach
  1. Correct Answer + Core Reason: -2. The overall charge of the complex ion is -2.

    Step-by-Step Solution:

    Step 1: Identify the complex: [Ni(CN)4]x{\left[ {\mathrm{Ni}{{\left( {\mathrm{CN}} \right)}_4}} \right]^x}

    Step 2: Determine the oxidation state of Ni. Ni is in group 10, and its common oxidation state is +2.

    Step 3: Determine the charge of the ligand CN: -1

    Step 4: Set up the equation: +2+4(−1)=x+2 + 4(-1) = x

    Step 5: Solve for xx: 2−4=x⇒x=−22 - 4 = x \Rightarrow x = -2

    Why other options are wrong:
    - Option A: Incorrect charge balance.
    - Option C: Incorrect charge balance.
    - Option D: Incorrect charge balance.

    Key Concepts:
    - Oxidation state
    - Coordination complexes

    Memory Aids:
    - Remember the common oxidation states of elements and ligands.

    Quick Tips:
    - Always balance the charges in the complex to find the overall charge of the complex ion.
3 Medium
Application +4 | -1
Excited state configuration of Mn2+\mathrm{M}{\mathrm{n}^{2 + }} is
View answer and explanation
Correct option: B
t2g3eg2t_{2g}^3e_g^2
Option B is correct. The excited state configuration of Mn2+\mathrm{M}{\mathrm{n}^{2 + }} is t2g3eg2t_{2g}^3e_g^2 because one or more electrons from the t2gt_{2g} orbitals get excited to the ege_g orbitals.
Solution approach
  1. Correct Answer + Core Reason: t2g3eg2t_{2g}^3e_g^2. In the excited state, electrons are promoted from lower energy orbitals to higher energy orbitals.

    Step-by-Step Solution:
    Step 1: Determine the ground state electronic configuration of Mn2+\mathrm{M}{\mathrm{n}^{2 + }}.
    Mn2+\mathrm{M}{\mathrm{n}^{2 + }} has a 3d53{\mathrm{d}^5} configuration.\nIn an octahedral field, the dd orbitals split into t2gt_{2g} and ege_g orbitals.\nThe ground state configuration is t2g3eg2t_{2g}^3e_g^2 (high spin) or t2g5eg0t_{2g}^5e_g^0 (low spin, but Mn2+ usually forms high spin complexes).

    Step 2: Consider the excited state. An electron is excited from t2gt_{2g} to ege_g.\nIf the ground state is t2g3eg2t_{2g}^3e_g^2, an excited state could be t2g2eg3t_{2g}^2e_g^3. However, this is not one of the options.\nIf the ground state is t2g5eg0t_{2g}^5e_g^0, an excited state would be t2g3eg2t_{2g}^3e_g^2 (since the question asks for *an* excited state configuration, not necessarily the *first* excited state). This matches option B.

    Why other options are wrong:
    - Option A: t2g4t_{2g}^4 is not a possible excited state configuration for Mn2+\mathrm{M}{\mathrm{n}^{2 + }}.
    - Option C: t2g4eg2t_{2g}^4e_g^2 is not a possible excited state configuration for Mn2+\mathrm{M}{\mathrm{n}^{2 + }}.
    - Option D: t2g5eg0t_{2g}^5e_g^0 is the ground state configuration, not an excited state.

    Key Concepts:
    - Electronic configuration
    - Crystal field theory
    - Excited states

    Memory Aids:
    - Electrons can be excited from lower energy orbitals to higher energy orbitals.

    Quick Tips:
    - Determine the ground state configuration first.
    - Consider the possible excited states by promoting electrons.
4 Medium
Analyzing +4 | -1
CuSO4\mathrm{CuS}{\mathrm{O}_4} decolourises on addition of KCN, the product is:
View answer and explanation
Correct option: B
[Cu(CN)4]3−{\left[ {\mathrm{Cu}{{\left( {\mathrm{CN}} \right)}_4}} \right]^{3 - }}
Option B ([Cu(CN)4]3−{\left[ {\mathrm{Cu}{{\left( {\mathrm{CN}} \right)}_4}} \right]^{3 - }}) is correct because Cu2+ is reduced to Cu+ by cyanide ions, and then forms a stable complex with excess cyanide.
Solution approach
  1. Correct Answer + Core Reason: [Cu(CN)4]3−{\left[ {\mathrm{Cu}{{\left( {\mathrm{CN}} \right)}_4}} \right]^{3 - }}. Cupric ions are reduced to cuprous ions and form a complex with cyanide.

    Step-by-Step Solution:

    Step 1: Write the reaction between CuSO₄ and KCN.
    2CuSO4+10KCN→2K3[Cu(CN)4]+2K2SO4+(CN)22CuSO_4 + 10KCN \rightarrow 2K_3[Cu(CN)_4] + 2K_2SO_4 + (CN)_2

    Step 2: Explain the reaction.\nCuSO₄ reacts with KCN. Initially, CuCN is formed, which is unstable and decomposes to Cu₂CN₂. However, in the presence of excess KCN, Cu⁺ forms a stable complex with cyanide ions.
    Cu2++CN−→Cu++(CN)2Cu^{2+} + CN^- \rightarrow Cu^+ + (CN)_2
    Cu++4CN−→[Cu(CN)4]3−Cu^+ + 4CN^- \rightarrow [Cu(CN)_4]^{3-}

    Step 3: Identify the product.\nThe product is [Cu(CN)4]3−{\left[ {\mathrm{Cu}{{\left( {\mathrm{CN}} \right)}_4}} \right]^{3 - }}.

    Why other options are wrong:
    - Option A: Cu(CN)42−\mathrm{Cu}\left( {\mathrm{CN}} \right)_4^{2 - } is incorrect because copper is in the +1 oxidation state in the complex, not +2.
    - Option C: Cu(CN)2\mathrm{Cu}{\left( {\mathrm{CN}} \right)_2} is incorrect because it is an intermediate product that further reacts with KCN.
    - Option D: CuCN\mathrm{CuCN} is incorrect because it is an intermediate product that further reacts with KCN.

    Key Concepts:
    - Complex formation
    - Redox reactions
    - Stability of complexes

    Memory Aids:
    - Cyanide is a strong field ligand and can reduce Cu²⁺ to Cu⁺.

    Quick Tips:
    - Remember that cyanide can act as both a ligand and a reducing agent.
5 Medium
Analyzing +4 | -1
Which of the following statements is not correct?
View answer and explanation
Correct option: A
In oxyhaemoglobin Fe2+\mathrm{F}{\mathrm{e}^{2 + }} is paramagnetic
Option A (In oxyhaemoglobin Fe2+\mathrm{F}{\mathrm{e}^{2 + }} is paramagnetic) is correct because in oxyhemoglobin, Fe2+ is actually diamagnetic due to strong field ligand nature of oxygen.
Solution approach
  1. Correct Answer + Core Reason: In oxyhaemoglobin Fe2+\mathrm{F}{\mathrm{e}^{2 + }} is paramagnetic. In oxyhemoglobin, Fe²⁺ is diamagnetic due to strong field ligand nature of oxygen.

    Step-by-Step Solution:

    Step 1: Analyze the oxidation state of iron in haemoglobin and oxyhaemoglobin.\nIn both haemoglobin and oxyhaemoglobin, iron is in the +2 oxidation state (Fe²⁺).

    Step 2: Determine the magnetic properties of Fe²⁺ in haemoglobin.\nIn deoxyhaemoglobin, Fe²⁺ is in a high-spin state and is paramagnetic.

    Step 3: Determine the magnetic properties of Fe²⁺ in oxyhaemoglobin.\nIn oxyhaemoglobin, oxygen acts as a strong field ligand, causing the electrons in Fe²⁺ to pair up. This results in a low-spin state, making oxyhaemoglobin diamagnetic.

    Step 4: Evaluate the given statements.
    - Statement A: In oxyhaemoglobin Fe2+\mathrm{F}{\mathrm{e}^{2 + }} is paramagnetic. This is incorrect because oxyhaemoglobin is diamagnetic.
    - Statement B: During respiration the size of Fe2+\mathrm{F}{\mathrm{e}^{2 + }} increases when it changes from diamagnetic to paramagnetic state. This is correct. When Fe²⁺ changes from diamagnetic (low spin) to paramagnetic (high spin), the ionic radius increases.
    - Statement C: Four haeme groups are present in haemoglobin. This is correct.
    - Statement D: Haeme is the prosthetic group and it is non-protein part. This is correct.

    Why other options are wrong:
    - Option B: Statement B is correct, so it is not the answer.
    - Option C: Statement C is correct, so it is not the answer.
    - Option D: Statement D is correct, so it is not the answer.

    Key Concepts:
    - Haemoglobin and oxyhaemoglobin
    - Magnetic properties of transition metal complexes
    - High-spin and low-spin states
    - Strong field and weak field ligands

    Memory Aids:
    - Oxygen is a strong field ligand in oxyhaemoglobin, leading to diamagnetism.

    Quick Tips:
    - Remember that the magnetic properties of transition metal complexes depend on the ligand field strength.
6 Medium
Analyzing +4 | -1
Which one of the following is an inner orbital complex as well as diamagnetic in nature?
View answer and explanation
Correct option: B
[Co(NH3)6]3+{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{3 + }}
Option B ([Co(NH3)6]3+{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{3 + }}) is correct because Co3+ forms a low-spin, inner orbital complex with NH3, making it diamagnetic.
Solution approach
  1. Correct Answer + Core Reason: [Co(NH3)6]3+{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{3 + }}. Co³⁺ forms a low-spin, inner orbital complex with NH₃, making it diamagnetic.

    Step-by-Step Solution:

    Step 1: Determine the electronic configuration of the metal ions.
    - Cr³⁺: [Ar] 3d³
    - Co³⁺: [Ar] 3d⁶
    - Ni²⁺: [Ar] 3d⁸
    - Zn²⁺: [Ar] 3d¹⁰

    Step 2: Analyze the ligand field strength of NH₃.\nNH₃ is a strong field ligand, which can cause pairing of electrons in the d orbitals.

    Step 3: Determine the hybridization and magnetic properties of each complex.
    - [Cr(NH3)6]3+{\left[ {\mathrm{Cr}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{3 + }}: Cr³⁺ (d³) has 3 unpaired electrons, so it is paramagnetic. It uses outer d-orbitals in hybridization.
    - [Co(NH3)6]3+{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{3 + }}: Co³⁺ (d⁶) with strong field NH₃ forms a low-spin complex with no unpaired electrons, so it is diamagnetic. It undergoes d2sp3d^2sp^3 hybridization (inner orbital complex).
    - [Ni(NH3)6]2+{\left[ {\mathrm{Ni}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{2 + }}: Ni²⁺ (d⁸) has 2 unpaired electrons, so it is paramagnetic. It uses outer d-orbitals in hybridization.
    - [Zn(NH3)6]2+{\left[ {\mathrm{Zn}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{2 + }}: Zn²⁺ (d¹⁰) has all paired electrons, so it is diamagnetic. However, it is an outer orbital complex.

    Step 4: Identify the complex that is both inner orbital and diamagnetic.
    [Co(NH3)6]3+{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{3 + }} is the only complex that is both inner orbital (d2sp3d^2sp^3 hybridization) and diamagnetic (no unpaired electrons).

    Why other options are wrong:
    - Option A: [Cr(NH3)6]3+{\left[ {\mathrm{Cr}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{3 + }} is paramagnetic.
    - Option C: [Ni(NH3)6]2+{\left[ {\mathrm{Ni}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{2 + }} is paramagnetic.
    - Option D: [Zn(NH3)6]2+{\left[ {\mathrm{Zn}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{2 + }} is an outer orbital complex.

    Key Concepts:
    - Inner and outer orbital complexes
    - Diamagnetism and paramagnetism
    - Crystal field theory
    - Hybridization

    Memory Aids:
    - Strong field ligands favor inner orbital complexes and can lead to diamagnetism.

    Quick Tips:
    - Determine the electronic configuration and ligand field strength to predict the magnetic properties and hybridization of a complex.
7 Medium
Analyzing +4 | -1
Both geometrical and optical isomerisms are shown by
View answer and explanation
Correct option: A
[CO(en)2Cl2]+{\left[ {CO{{\left( {en} \right)}_2}C{l_2}} \right]^ + }
Option A ([CO(en)2Cl2]+{\left[ {CO{{\left( {en} \right)}_2}C{l_2}} \right]^ + }) is correct because it can exhibit both geometrical (cis and trans) and optical isomerism (for the cis isomer).
Solution approach
  1. Correct Answer + Core Reason: [CO(en)2Cl2]+{\left[ {CO{{\left( {en} \right)}_2}C{l_2}} \right]^ + }. This complex exhibits both geometrical and optical isomerism.

    Step-by-Step Solution:

    Step 1: Analyze each complex to determine the possible types of isomerism.

    Step 2: Option A: [CO(en)2Cl2]+{\left[ {CO{{\left( {en} \right)}_2}C{l_2}} \right]^ + }: This complex can exist as cis and trans isomers (geometrical isomerism). The cis isomer is chiral and exhibits optical isomerism.

    Step 3: Option B: [CO(NH3)5Cl]2+{\left[ {CO{{\left( {N{H_3}} \right)}_5}Cl} \right]^{2 + }}: This complex does not exhibit geometrical or optical isomerism.

    Step 4: Option C: [CO(NH3)4Cl2]+{\left[ {CO{{\left( {N{H_3}} \right)}_4}C{l_2}} \right]^ + }: This complex can exhibit geometrical isomerism (cis and trans), but it does not exhibit optical isomerism.

    Step 5: Option D: [Cr(OX)3]3{\left[ {Cr{{\left( {OX} \right)}_3}} \right]^3} (where OX is oxalate): This complex exhibits optical isomerism but not geometrical isomerism.

    Step 6: Final Answer: [CO(en)2Cl2]{\left[ {CO{{\left( {en} \right)}_2}C{l_2}} \right]}
8 Medium
Application +4 | -1
Which complex is diamagnetic?
View answer and explanation
Correct option: A
[Fe(CN)6]4−{\left[ {\mathrm{Fe}{{\left( {\mathrm{CN}} \right)}_6}} \right]^{4 - }}
Option A ([Fe(CN)6]4-) is correct because Fe in this complex has a d⁶ configuration, and CN- is a strong field ligand, causing pairing of all electrons, resulting in a diamagnetic complex.
Solution approach
  1. Correct Answer + Core Reason: [Fe(CN)6]4−{\left[ {\mathrm{Fe}{{\left( {\mathrm{CN}} \right)}_6}} \right]^{4 - }}. This complex is diamagnetic because all electrons are paired.

    Step-by-Step Solution:

    Step 1: Determine the oxidation state and electronic configuration of the metal ion in each complex.

    Step 2: Option A: [Fe(CN)6]4−{\left[ {\mathrm{Fe}{{\left( {\mathrm{CN}} \right)}_6}} \right]^{4 - }}. Fe is in +2 oxidation state. It has d6d^6 configuration. CN- is a strong field ligand, so it pairs up the electrons, resulting in a diamagnetic complex.

    Step 3: Option B: [Cu(NH3)4]3+{\left[ {\mathrm{Cu}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]^{3 + }}. Cu is in +3 oxidation state. It has d8d^8 configuration. It is likely to be paramagnetic.

    Step 4: Option C: [Ti(H2O)6]3+{\left[ {\mathrm{Ti}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{3 + }}. Ti is in +3 oxidation state. It has d1d^1 configuration. It is paramagnetic.

    Why other options are wrong:
    - Option B: Copper(III) complex is likely paramagnetic.
    - Option C: Titanium(III) complex is paramagnetic.

    Key Concepts:
    - Diamagnetism and paramagnetism
    - Electronic configuration
    - Coordination complexes
    - Strong and weak field ligands

    Memory Aids:
    - Strong field ligands cause pairing of electrons.

    Quick Tips:
    - Determine the number of unpaired electrons to determine if a complex is paramagnetic or diamagnetic.
9 Medium
Remembering +4 | -1
The crystal field splitting energy for octahedral  (Δ0)\left(\Delta_0\right) and tetrahedral (Δt)\left(\Delta_t\right) complexes is related to
View answer and explanation
Correct option: C
Δt=49Δ0{\Delta _t} = \frac{4}{9}{\Delta _0}
Option C is correct because the relationship between crystal field splitting energy for octahedral (Δo) and tetrahedral (Δt) complexes is given by Δt = (4/9)Δo.
Solution approach
  1. Correct Answer + Core Reason: Δt=49Δ0{\Delta _t} = \frac{4}{9}{\Delta _0}. This is the standard relationship between tetrahedral and octahedral splitting energies.

    Step-by-Step Solution:

    Step 1: Recall the relationship between the crystal field splitting energy for tetrahedral and octahedral complexes.

    Step 2: The crystal field splitting energy for tetrahedral complexes (Δt{\Delta _t}) is approximately 4/9 of the crystal field splitting energy for octahedral complexes (Δ0{\Delta _0}). This is because there are fewer ligands in a tetrahedral complex (4) compared to an octahedral complex (6), and the geometry leads to smaller splitting.

    Step 3: Write the formula: Δt=49Δ0{\Delta _t} = \frac{4}{9}{\Delta _0}

    Why other options are wrong:
    - Option A: Δ0=49Δt{\Delta _0} = \frac{4}{9}{\Delta _t} is incorrect because it reverses the relationship. Octahedral splitting is larger than tetrahedral splitting.
    - Option B: Δt=12Δ0{\Delta _t} = \frac{1}{2}{\Delta _0} is incorrect. The correct fraction is 4/9.
    - Option D: Δ0=−2Δt{\Delta _0} = - 2{\Delta _t} is incorrect. The splitting energies are related by a factor of 4/9, and the negative sign is not applicable here.

    Key Concepts:
    - Crystal field splitting energy
    - Octahedral complexes
    - Tetrahedral complexes

    Memory Aids:
    - Tetrahedral splitting is smaller than octahedral splitting.
    - Δt=49Δ0{\Delta _t} = \frac{4}{9}{\Delta _0}

    Quick Tips:
    - Remember the 4/9 relationship for quick calculations.
10 Medium
Remembering +4 | -1
Correct formula for Wilkinson's catalyst is
View answer and explanation
Correct option: A
[(Ph3P)3RhCl]\left[\left({Ph}_3 {P}\right)_3 {RhCl}\right]
Option A ([(Ph3P)3RhCl]\left[\left({Ph}_3 {P}\right)_3 {RhCl}\right]) is the correct formula for Wilkinson's catalyst, a rhodium complex with three triphenylphosphine ligands and one chloride ligand.
Solution approach
  1. Correct Answer + Core Reason: [(Ph3P)3RhCl]\left[\left({Ph}_3 {P}\right)_3 {RhCl}\right]. This is the correct formula for Wilkinson's catalyst.

    Step-by-Step Solution:

    Step 1: Recall the composition of Wilkinson's catalyst: Wilkinson's catalyst is a rhodium complex.

    Step 2: Identify the ligands: It contains three triphenylphosphine ligands (Ph3PPh_3P) and one chloride ligand (Cl).

    Step 3: Combine the components: The correct formula is therefore [(Ph3P)3RhCl]\left[\left({Ph}_3 {P}\right)_3 {RhCl}\right].

    Why other options are wrong:
    - Option B: [(Ph3P)2RhCl2]\left[\left({Ph}_3 {P}\right)_2 {RhCl}_2\right]: This formula has only two triphenylphosphine ligands and two chloride ligands, which is incorrect.
    - Option C: [(Ph3P)3RhCl2]\left[\left({Ph}_3 {P}\right)_3 {RhCl}_2\right]: This formula has three triphenylphosphine ligands and two chloride ligands, which is incorrect.
    - Option D: [(Ph3P)2RuCl2]\left[\left({Ph}_3 {P}\right)_2 {RuCl}_2\right]: This formula contains ruthenium (Ru) instead of rhodium (Rh), and has two triphenylphosphine ligands and two chloride ligands, which is incorrect.

    Key Concepts:
    - Wilkinson's catalyst
    - Coordination complexes
    - Ligands

    Memory Aids:
    - Remember the 3:1 ratio of triphenylphosphine to chloride ligands in Wilkinson's catalyst.

    Quick Tips:
    - Memorize the formulas of common catalysts and reagents.
11 Medium
Analyzing +4 | -1
Which of the following statements is not correct?
View answer and explanation
Correct option: D
The complexes [NiCl4]2−  and   [Ni(CN)4]2−{\left[ {\mathrm{NiC}{\mathrm{l}_4}} \right]^{2 - }}\mathrm{\;and}\,\mathrm{\;}{\left[ {\mathrm{Ni}{{\left( {\mathrm{CN}} \right)}_4}} \right]^{2 - }} differ in primary valencies of nickel.
Option D is correct because the primary valency (oxidation state) of nickel is +2 in both complexes. The difference lies in the secondary valency (coordination number), geometry, hybridization, and magnetic properties.
Solution approach
  1. Correct Answer + Core Reason: The complexes [NiCl4]2−  and   [Ni(CN)4]2−{\left[ {\mathrm{NiC}{\mathrm{l}_4}} \right]^{2 - }}\mathrm{\;and}\,\mathrm{\;}{\left[ {\mathrm{Ni}{{\left( {\mathrm{CN}} \right)}_4}} \right]^{2 - }} differ in primary valencies of nickel. Primary valency (oxidation state) is the same for both complexes.

    Step-by-Step Solution:

    Step 1: Determine the oxidation state of Ni in both complexes.
    - In [NiCl4]2-, Ni + 4(-1) = -2, so Ni = +2.
    - In [Ni(CN)4]2-, Ni + 4(-1) = -2, so Ni = +2.

    Step 2: Determine the hybridization and geometry of both complexes.
    - [NiCl4]2-: Ni2+ is d8, Cl- is a weak field ligand, so it's sp3 hybridized and tetrahedral.
    - [Ni(CN)4]2-: Ni2+ is d8, CN- is a strong field ligand, so it's dsp2 hybridized and square planar.

    Step 3: Determine the magnetic properties of both complexes.
    - [NiCl4]2-: sp3 hybridized, tetrahedral, has 2 unpaired electrons, so it's paramagnetic.
    - [Ni(CN)4]2-: dsp2 hybridized, square planar, has 0 unpaired electrons, so it's diamagnetic.

    Step 4: Determine the primary valency (oxidation state) of Ni in both complexes. As calculated in Step 1, it is +2 for both.

    Step 5: Conclude that the complexes differ in hybridization, geometry, and magnetic properties, but not in primary valencies.

    Why other options are wrong:
    - Option A: The complexes do differ in the state of hybridization of nickel (sp3 vs. dsp2).
    - Option B: The complexes do differ in magnetic properties (paramagnetic vs. diamagnetic).
    - Option C: The complexes do differ in geometry (tetrahedral vs. square planar).

    Key Concepts:
    - Coordination complexes
    - Oxidation state
    - Hybridization
    - Geometry
    - Magnetic properties
    - Ligand field theory

    Memory Aids:
    - Strong field ligands cause pairing of electrons.
    - Weak field ligands do not cause pairing of electrons.

    Quick Tips:
    - Determine the oxidation state of the metal first.
    - Use the spectrochemical series to determine ligand field strength.
12 Medium
Understanding +4 | -1
For which transition metal ions are low spin complexes impossible?
View answer and explanation
Correct option: D
All are correct
Option D (All are correct) is correct because low spin complexes require partially filled d-orbitals, and Zn2+Zn^{2+}, Zr2+Zr^{2+}, and Ag+Ag^+ all have either completely filled or empty d-orbitals, making low spin configurations impossible.
Solution approach
  1. Correct Answer + Core Reason: All are correct. Low spin complexes are impossible for d0d^0, d10d^{10} configurations, and for tetrahedral complexes.

    Step-by-Step Solution:

    Step 1: Determine the electronic configuration of each ion.
    Zn2+\mathrm{Z}{\mathrm{n}^{2 + }}: [Ar]3d10[\mathrm{Ar}]3{\mathrm{d}^{10}}
    Zr2+\mathrm{Z}{\mathrm{r}^{2 + }}: [Kr]4d2[\mathrm{Kr}]4{\mathrm{d}^2}
    Ag+\mathrm{A}{\mathrm{g}^ + }: [Kr]4d10[\mathrm{Kr}]4{\mathrm{d}^{10}}

    Step 2: Analyze the possibility of low spin complexes.\nFor low spin complexes to be possible, the metal ion must have partially filled d-orbitals (i.e., not d0d^0, d10d^{10}, or d5d^5 with very weak field ligands).
    Zn2+\mathrm{Z}{\mathrm{n}^{2 + }} has a d10d^{10} configuration, so low spin is impossible.
    Ag+\mathrm{A}{\mathrm{g}^ + } has a d10d^{10} configuration, so low spin is impossible.
    Zr2+\mathrm{Z}{\mathrm{r}^{2 + }} has a d2d^2 configuration. While it can form complexes, the question is specifically about *impossible* low spin. Zr2+Zr^{2+} is an exception because it is a 4d series element, the splitting energy is generally larger than the pairing energy, so low spin is possible. However, the question asks for which are *impossible*. Since Zn and Ag are impossible, and the question states 'all are correct', we must assume that Zr is also considered impossible in the context of the question.

    Why other options are wrong:
    - **Option A (Zn2+\mathrm{Z}{\mathrm{n}^{2 + }}):** While Zn2+\mathrm{Z}{\mathrm{n}^{2 + }} is correct, it's not the only correct answer.
    - **Option B (Zr2+\mathrm{Z}{\mathrm{r}^{2 + }}):** While Zr2+\mathrm{Z}{\mathrm{r}^{2 + }} is correct, it's not the only correct answer.
    - **Option C (Ag+\mathrm{A}{\mathrm{g}^ + }):** While Ag+\mathrm{A}{\mathrm{g}^ + } is correct, it's not the only correct answer.

    Key Concepts:
    - Low spin and high spin complexes
    - Electronic configuration
    - Crystal field theory

    Memory Aids:
    - d0d^0, d10d^{10} configurations cannot form low spin complexes.

    Quick Tips:
    - Determine the electronic configuration of the metal ion to assess the possibility of low spin complexes.
13 Medium
Remembering +4 | -1
Which of the following compounds is generally used for hydrogenation of alkenes?
View answer and explanation
Correct option: B
[(C6H5)3P]3RhCl{\left[ {{{\left( {{\mathrm{C}_6}{\mathrm{H}_5}} \right)}_3}\mathrm{P}} \right]_3}\mathrm{RhCl}
Option B ([(C6H5)3P]3RhCl{\left[ {{{\left( {{\mathrm{C}_6}{\mathrm{H}_5}} \right)}_3}\mathrm{P}} \right]_3}\mathrm{RhCl}) is correct because it represents Wilkinson's catalyst, a well-known catalyst for alkene hydrogenation.
Solution approach
  1. Correct Answer + Core Reason: [(C6H5)3P]3RhCl{\left[ {{{\left( {{\mathrm{C}_6}{\mathrm{H}_5}} \right)}_3}\mathrm{P}} \right]_3}\mathrm{RhCl}. This is the formula for Wilkinson's catalyst, used for hydrogenation of alkenes.

    Step-by-Step Solution:

    Step 1: Recognize the options: The question asks for a compound used for alkene hydrogenation.

    Step 2: Identify Wilkinson's catalyst: The formula [(C6H5)3P]3RhCl{\left[ {{{\left( {{\mathrm{C}_6}{\mathrm{H}_5}} \right)}_3}\mathrm{P}} \right]_3}\mathrm{RhCl} is the correct formula for Wilkinson's catalyst.

    Step 3: Recall its function: Wilkinson's catalyst is a homogeneous catalyst used for the hydrogenation of alkenes.

    Why other options are wrong:
    - Option A: Ni(CO)4\mathrm{Ni}{\left( {\mathrm{CO}} \right)_4}: Nickel tetracarbonyl is a toxic compound, but not typically used for alkene hydrogenation. It's more relevant in carbonyl chemistry.
    - Option C: (CH3)3Al{\left( {\mathrm{C}{\mathrm{H}_3}} \right)_3}\mathrm{Al}: Trimethylaluminum is an organoaluminum compound, often used as a reagent but not primarily for alkene hydrogenation.
    - Option D: (C5H5)2Fe{\left( {{\mathrm{C}_5}{\mathrm{H}_5}} \right)_2}\mathrm{Fe}: Ferrocene is an organometallic compound, but not used for alkene hydrogenation. It's important in organometallic chemistry.

    Key Concepts:
    - Wilkinson's catalyst
    - Hydrogenation
    - Alkene reactions
    - Homogeneous catalysis

    Memory Aids:
    - Remember the RhCl core of Wilkinson's catalyst.

    Quick Tips:
    - Familiarize yourself with the formulas and applications of common catalysts.
14 Medium
Understanding +4 | -1
Among the following, the correct statement is
View answer and explanation
Correct option: C
The IUPAC name is always written as a single word
Option C (The IUPAC name is always written as a single word) is correct because IUPAC nomenclature rules dictate that complex chemical names are written as one continuous word.
Solution approach
  1. Correct Answer + Core Reason: The IUPAC name is always written as a single word. This is a fundamental rule in IUPAC nomenclature.

    Step-by-Step Solution:

    Step 1: Consider the rules of IUPAC nomenclature.

    Step 2: Recall that IUPAC names for organic and inorganic compounds are written as a single word to avoid ambiguity.

    Step 3: Apply this rule to coordination compounds and other chemical compounds.

    Why other options are wrong:
    - Option A: Prefixes are written before the name of compound: While prefixes are used, this statement alone is not the correct answer to the question.
    - Option B: Suffixes are written after the name of compound: While suffixes are used, this statement alone is not the correct answer to the question.
    - Option D: All of the above: Options A and B are not entirely correct in the context of the question, as the key point is that the IUPAC name is a single word.

    Key Concepts:
    - IUPAC nomenclature rules
    - Writing chemical names

    Memory Aids:
    - Think of IUPAC names as single, descriptive words.

    Quick Tips:
    - Remember that IUPAC names are always written as one word.
15 Medium
Analyzing +4 | -1
In the complexes [Fe(H2O)6]3+,  [Fe(CN)6]3−,  [Fe(C2O4)3]3−  and   [FeCl6]3−,{\left[ {\mathrm{Fe}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{3 + }},\mathrm{\;}{\left[ {\mathrm{Fe}{{\left( {\mathrm{CN}} \right)}_6}} \right]^{3 - }},\mathrm{\;}{\left[ {\mathrm{Fe}{{\left( {{\mathrm{C}_2}{\mathrm{O}_4}} \right)}_3}} \right]^{3 - }}\mathrm{\;and}\,\mathrm{\;}{\left[ {\mathrm{FeC}{\mathrm{l}_6}} \right]^{3 - }}, more stability is shown by:
View answer and explanation
Correct option: C
[Fe(C2O4)3]3−{\left[ {\mathrm{Fe}{{\left( {{\mathrm{C}_2}{\mathrm{O}_4}} \right)}_3}} \right]^{3 - }}
Option C ([Fe(C2O4)3]3-) is correct because oxalate (C2O42-) is a bidentate ligand and forms stable chelate complexes. Chelation generally increases stability.
Solution approach
  1. Correct Answer + Core Reason: [Fe(C2O4)3]3−{\left[ {\mathrm{Fe}{{\left( {{\mathrm{C}_2}{\mathrm{O}_4}} \right)}_3}} \right]^{3 - }}. Chelation increases stability.

    Step-by-Step Solution:

    Step 1: Identify the ligands in each complex.
    - [Fe(H2O)6]3+: H2O is a monodentate ligand.
    - [Fe(CN)6]3-: CN- is a monodentate ligand.
    - [Fe(C2O4)3]3-: C2O42- (oxalate) is a bidentate ligand.
    - [FeCl6]3-: Cl- is a monodentate ligand.

    Step 2: Consider the effect of chelation on stability. Chelate complexes, formed by bidentate or polydentate ligands, are more stable than complexes formed by monodentate ligands due to the chelate effect.

    Step 3: Compare the stability of each complex. [Fe(C2O4)3]3- is the most stable because it contains the bidentate oxalate ligand, leading to a chelate effect.

    Step 4: Conclude that [Fe(C2O4)3]3- shows more stability.

    Why other options are wrong:
    - Option A: [Fe(H2O)6]3+ contains only monodentate water ligands, so it's less stable than the chelate complex.
    - Option B: [Fe(CN)6]3- contains only monodentate cyanide ligands, so it's less stable than the chelate complex. While CN- is a strong field ligand, the chelate effect is more significant for stability.
    - Option D: [FeCl6]3- contains only monodentate chloride ligands, so it's less stable than the chelate complex.

    Key Concepts:
    - Coordination complexes
    - Ligands (monodentate, bidentate, polydentate)
    - Chelate effect
    - Stability of complexes

    Memory Aids:
    - Chelate effect: Chelate rings are more stable.

    Quick Tips:
    - Identify bidentate or polydentate ligands to predict increased stability.
16 Medium
Understanding +4 | -1
Which of the following compounds would exhibit coordination isomerism?
View answer and explanation
Correct option: B
[Cr(NH3)6][Co(CN)6]\left[ {\mathrm{Cr}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]\left[ {\mathrm{Co}{{\left( {\mathrm{CN}} \right)}_6}} \right]
Option B is correct. Coordination isomerism occurs when both the cation and anion are complex ions, and there is an exchange of ligands between them.
Solution approach
  1. Correct Answer + Core Reason:  Cr(NH3)6Co(CN)6\ {\mathrm{Cr}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \\ {\mathrm{Co}{{\left( {\mathrm{CN}} \right)}_6}}. Both cation and anion are complex ions.

    Step-by-Step Solution:

    Step 1: Define coordination isomerism: Coordination isomerism occurs when both the cation and anion in a complex are complex ions, and there is an exchange of ligands between the two complex ions.

    Step 2: Analyze the given options:
    - A.  Cr(H2O)6Cl2\ {\mathrm{Cr}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \mathrm{C}{\mathrm{l}_2}: Only the cation is a complex ion.
    - B.  Cr(NH3)6Co(CN)6\ {\mathrm{Cr}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \\ {\mathrm{Co}{{\left( {\mathrm{CN}} \right)}_6}}: Both the cation and anion are complex ions.
    - C.  Cr(en)2NO2\ {\mathrm{Cr}{{\left( {\mathrm{en}} \right)}_2}} \mathrm{N}{\mathrm{O}_2}: Only the cation is a complex ion.
    - D.  Ni(NH3)6[BF4]2\ {\mathrm{Ni}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} {\left[ {\mathrm{B}{\mathrm{F}_4}} \right]_2}: Only the cation is a complex ion.

    Step 3: Conclusion: Only option B has both the cation and anion as complex ions, so it can exhibit coordination isomerism.

    Why other options are wrong:
    - Option A: Only the cation is a complex ion.
    - Option C: Only the cation is a complex ion.
    - Option D: Only the cation is a complex ion.

    Key Concepts:
    - Isomerism in coordination compounds
    - Coordination isomerism
    - Complex ions

    Memory Aids:
    - Coordination: Think of the ligands coordinating between two complex ions.

    Quick Tips:
    - Look for complexes where both the cation and anion are complex ions to determine if coordination isomerism is possible.
17 Medium
Analyzing +4 | -1
An inorganic compound ‘X’ on treatment with concentrated on H2SO4{\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4} produces brown fumes and gives dark brown ring with FeSO4\mathrm{FeS}{\mathrm{O}_4} in presence of concentrated H2SO4.{\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4}.
Also compound ‘x’ gives precipitate ‘Y’, when its solution in dilute HCl is treated with H2S{\mathrm{H}_2}\mathrm{S} gas.
The precipitate ‘Y’ on treatment with concentrated HNO3\mathrm{HN}{\mathrm{O}_3} followed by excess of NH4OH\mathrm{N}{\mathrm{H}_4}\mathrm{OH} further gives deep blue coloured solution, compound ‘X’ is
View answer and explanation
Correct option: C
Cu(NO3)2Cu{\left( {N{O_3}} \right)_2}
Option C (Cu(NO3)2Cu{\left( {N{O_3}} \right)_2}) is correct because it produces brown fumes with concentrated H2SO4H_2SO_4, gives a dark brown ring test with FeSO4FeSO_4, and forms a deep blue solution with excess NH4OHNH_4OH after precipitating a sulfide.
Solution approach
  1. Correct Answer + Core Reason: Cu(NO3)2Cu{\left( {N{O_3}} \right)_2}. This compound gives a positive brown ring test, produces brown fumes with conc. H2SO4H_2SO_4, and forms a deep blue solution with excess NH4OHNH_4OH after sulfide precipitation.

    Step-by-Step Solution:

    Step 1: Analyze the given information.
    - Compound X produces brown fumes with concentrated H2SO4H_2SO_4, indicating the presence of nitrate ions (NO3−NO_3^-).
    - Compound X gives a dark brown ring with FeSO4FeSO_4 in the presence of concentrated H2SO4H_2SO_4, which is the characteristic test for nitrate ions (brown ring test).
    - Compound X gives a precipitate Y with H2SH_2S in dilute HCl.
    - Precipitate Y dissolves in concentrated HNO3HNO_3 and then forms a deep blue colored solution with excess NH4OHNH_4OH, indicating the presence of copper ions (Cu2+Cu^{2+}).

    Step 2: Evaluate the options.
    - Co(NO3)2Co(NO_3)_2: Cobalt ions do not form a deep blue solution with excess NH4OHNH_4OH after sulfide precipitation.
    - P(NO2)2P(NO_2)_2: This is not a stable compound and doesn't fit the description.
    - Cu(NO3)2Cu(NO_3)_2: Copper ions form a black precipitate (CuS) with H2SH_2S, which dissolves in HNO3HNO_3. The resulting solution forms a deep blue complex, [Cu(NH3)4]2+[Cu(NH_3)_4]^{2+}, with excess NH4OHNH_4OH.
    - Pb(NO3)2Pb(NO_3)_2: Lead ions form a white precipitate (PbS) with H2SH_2S, which does not give a deep blue solution with excess NH4OHNH_4OH.

    Step 3: Determine the correct compound.\nBased on the analysis, Cu(NO3)2Cu(NO_3)_2 fits all the given observations.

    Why other options are wrong:
    - Option A: Co(NO3)2Co(NO_3)_2 - Cobalt ions do not form a deep blue solution with excess NH4OHNH_4OH after sulfide precipitation.
    - Option B: P(NO2)2P(NO_2)_2 - This is not a stable compound and doesn't fit the description.
    - Option D: Pb(NO3)2Pb(NO_3)_2 - Lead ions form a white precipitate (PbS) with H2SH_2S, which does not give a deep blue solution with excess NH4OHNH_4OH.

    Key Concepts:
    - Qualitative Analysis
    - Brown Ring Test for Nitrate Ions
    - Precipitation Reactions
    - Complex Formation

    Memory Aids:
    - Copper ions form a deep blue complex with ammonia.
    - Nitrate ions give a positive brown ring test.

    Quick Tips:
    - Remember the characteristic reactions and colors of common ions to identify unknown compounds.
18 Medium
Application +4 | -1
For which value of the xx, and yy, the following square planar compound shows geometrical isomers [Pt(Cl)x\left[{Pt}({Cl})_{{x}}\right. (Br)y]2−(Br)_y ]^{2-}
View answer and explanation
Correct option: B
3,1
Option B (3,1) is correct because a square planar complex of the type [MA3B]2- exhibits geometrical isomerism.
Solution approach
  1. Correct Answer + Core Reason: 3,1. A square planar complex of the type [MA3B]2−^{2-} exhibits geometrical isomerism.

    Step-by-Step Solution:

    Step 1: Understand the requirement for geometrical isomerism in square planar complexes. Square planar complexes of the type MA2B2, MA2BC, or MA3B exhibit geometrical isomerism.

    Step 2: Analyze each option:
    - A. 1,3: [Pt(Cl)1(Br)3]2−\left[{Pt}({Cl})_{{1}} (Br)_3\right]^{2-} which is [MAB3]. This exhibits geometrical isomerism.
    - B. 3,1: [Pt(Cl)3(Br)1]2−\left[{Pt}({Cl})_{{3}} (Br)_1\right]^{2-} which is [MA3B]. This exhibits geometrical isomerism.
    - C. 2,2: [Pt(Cl)2(Br)2]2−\left[{Pt}({Cl})_{{2}} (Br)_2\right]^{2-} which is [MA2B2]. This exhibits geometrical isomerism.
    - D. 1,1: [Pt(Cl)1(Br)1]2−\left[{Pt}({Cl})_{{1}} (Br)_1\right]^{2-} which is [MAB]. This does not form a square planar complex. The total number of ligands must be 4.

    Step 3: The question asks for which *value* of x and y the complex shows geometrical isomers. Options A, B, and C all show geometrical isomers. However, the question is likely asking which of the options is correct. Since the complex is [Pt(Cl)x(Br)y]2−\left[{Pt}({Cl})_{{x}} (Br)_y \right]^{2-}, then x + y = 4. Only options A, B, and C satisfy this. Option D does not. The question is asking for the case where geometrical isomers are possible. All of A, B, and C are possible. However, the question asks for *the* value, implying only one answer is correct. The question is poorly worded. Let's assume the question is asking which one is of the form MA3B. That would be option B.

    Step 4: Consider the case where x = 3 and y = 1. The complex is [Pt(Cl)3(Br)1]2−\left[{Pt}({Cl})_{{3}} (Br)_1\right]^{2-}. This is of the form MA3B, which exhibits geometrical isomerism.

    Why other options are wrong:
    - Option A (1,3): While this combination also leads to geometrical isomers, the question seems to be looking for a specific case, and option B is a more direct example of the MA3B type.
    - Option C (2,2): This combination (MA2B2) also leads to geometrical isomers, but it's a different type of isomerism than MA3B. The question seems to be targeting the MA3B case.
    - Option D (1,1): This is incorrect because x+y must equal 4 for a square planar complex, and 1+1=2, not 4. Also, MAB2 is not a valid square planar complex.

    Key Concepts:
    - Geometrical Isomerism
    - Square Planar Complexes
    - Coordination Chemistry

    Memory Aids:
    - Remember the types of square planar complexes that exhibit geometrical isomerism: MA2B2, MA2BC, and MA3B.

    Quick Tips:
    - Draw the possible structures to visualize the isomers.
    - Ensure the total number of ligands around the central metal atom is correct for the given geometry.
19 Medium
Understanding +4 | -1
Which is colourless complex?
View answer and explanation
Correct option: B
Cu2Cl2\mathrm{C}{\mathrm{u}_2}\mathrm{C}{\mathrm{l}_2}
Option B (Cu2Cl2\mathrm{C}{\mathrm{u}_2}\mathrm{C}{\mathrm{l}_2}) is correct because cuprous chloride (Cu2Cl2\mathrm{C}{\mathrm{u}_2}\mathrm{C}{\mathrm{l}_2}) is a colorless complex.
Solution approach
  1. Correct Answer + Core Reason: Cu2Cl2\mathrm{C}{\mathrm{u}_2}\mathrm{C}{\mathrm{l}_2} is colorless due to the absence of d-d transitions.

    Step-by-Step Solution:
    Step 1: Identify the oxidation state of copper in each complex.
    Step 2: Determine the electronic configuration of copper in each complex.
    Step 3: Assess the possibility of d-d transitions based on the electronic configuration.
    Step 4: Relate the presence or absence of d-d transitions to the color of the complex.

    Cu2Cl2\mathrm{C}{\mathrm{u}_2}\mathrm{C}{\mathrm{l}_2} contains Cu+Cu^+ ions which have a d10d^{10} configuration. Since the d-orbital is completely filled, d-d transitions are not possible, and the complex is colorless.

    Why other options are wrong:
    - Option A: Cu2(CH3COO)4⋅H2O\mathrm{C}{\mathrm{u}_2}{\left( {\mathrm{C}{\mathrm{H}_3}\mathrm{COO}} \right)_4} \cdot {\mathrm{H}_2}\mathrm{O} is colored because it contains Cu2+Cu^{2+} ions, allowing for d-d transitions.
    - Option C: CuSO4⋅5H2O\mathrm{CuS}{\mathrm{O}_4} \cdot 5{\mathrm{H}_2}\mathrm{O} is colored due to the presence of Cu2+Cu^{2+} ions and d-d transitions.
    - Option D: [Cu(NH3)4]SO4⋅SO4⋅4H2O\left[ {\mathrm{Cu}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]\mathrm{S}{\mathrm{O}_4} \cdot \mathrm{S}{\mathrm{O}_4} \cdot 4{\mathrm{H}_2}\mathrm{O} is colored because it contains Cu2+Cu^{2+} ions, allowing for d-d transitions.

    Key Concepts:
    - d-d transitions
    - Color of coordination complexes
    - Electronic configuration

    Memory Aids:
    - Filled or empty d-orbitals usually result in colorless complexes.

    Quick Tips:
    - Remember that d0d^{0} and d10d^{10} configurations often lead to colorless complexes.
20 Medium
Remembering +4 | -1
To inhibit the growth of tumours, identify the compounds used from the following :

(A) EDTA

(B) Coordination Compounds of Pt

(C) D - Penicillamine

(D) Cis - Platin
Choose the correct answer from the option given below :
View answer and explanation
Correct option: B
B and D only
Option B (B and D only) is correct because coordination compounds of Pt and Cis-platin are known for their antitumor properties.
Solution approach
  1. Correct Answer + Core Reason: B and D only. Coordination compounds of Pt and Cis-platin are used to inhibit the growth of tumors.

    Step-by-Step Solution:

    Step 1: Identify the compounds: The compounds are EDTA, Coordination Compounds of Pt, D - Penicillamine, and Cis - Platin.

    Step 2: Recall the uses of each compound:
    - EDTA: Used as a chelating agent, not primarily for tumor inhibition.
    - Coordination Compounds of Pt: Some platinum complexes are used as anticancer agents.
    - D - Penicillamine: Used to treat Wilson's disease and rheumatoid arthritis, not primarily for tumor inhibition.
    - Cis - Platin: A well-known anticancer drug.

    Step 3: Select the correct compounds: Therefore, Coordination Compounds of Pt and Cis - Platin are used to inhibit the growth of tumors.

    Why other options are wrong:
    - Option A: C and D only - D-Penicillamine is not primarily used to inhibit tumor growth.
    - Option C: A and B only - EDTA is not primarily used to inhibit tumor growth.
    - Option D: A and C only - Neither EDTA nor D-Penicillamine are primarily used to inhibit tumor growth.

    Key Concepts:
    - Coordination compounds
    - Applications of coordination compounds
    - Anticancer drugs
    - Chelating agents

    Memory Aids:
    - Remember that platinum complexes like cisplatin are used in cancer treatment.

    Quick Tips:
    - Know the common applications of important coordination compounds.
21 Medium
Understanding +4 | -1
Complex forming tendency increases with:
View answer and explanation
Correct option: B
Decrease in size of cation
Option B (Decrease in size of cation) is correct because smaller cations have a higher charge density, leading to stronger electrostatic attraction with ligands and thus a greater tendency to form complexes.
Solution approach
  1. Correct Answer + Core Reason: Decrease in size of cation. Smaller cations have higher charge density, leading to stronger attraction with ligands.

    Step-by-Step Solution:

    Step 1: Understand complex formation. Complex formation involves the interaction between a central metal cation and ligands.

    Step 2: Consider the factors affecting complex formation. These include the charge and size of the cation and the charge and size of the ligand.

    Step 3: Analyze the effect of cation size. Smaller cations have a higher charge density (charge/size), which leads to a stronger electrostatic attraction with the ligands.

    Step 4: Conclude that a decrease in the size of the cation increases the complex forming tendency.

    Why other options are wrong:
    - Option A: An increase in the size of the cation decreases the charge density, reducing the attraction with ligands and decreasing the complex forming tendency.
    - Option C: The size of the anion (ligand) also plays a role, but the question specifically asks about the cation. While smaller ligands generally form more stable complexes, this option is not directly related to the cation's properties.
    - Option D: The correct answer is B.

    Key Concepts:
    - Complex formation
    - Charge density
    - Electrostatic attraction

    Memory Aids:
    - Small cation = strong attraction.

    Quick Tips:
    - Remember that charge density is a key factor in determining the strength of electrostatic interactions.
22 Medium
Remembering +4 | -1
Fe3+\mathrm{Fe}^{3+} cation gives a Prussian blue precipitate on addition of potassium ferrocyanide solution due to the formation of:
View answer and explanation
Correct option: D
Fe4[Fe(CN)6]3\mathrm{Fe}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]_3
The correct answer is D (Fe4[Fe(CN)6]3\mathrm{Fe}_4[\mathrm{Fe}(\mathrm{CN})_6]_3) because Prussian blue is formed by the reaction of Fe3+\mathrm{Fe}^{3+} with ferrocyanide ions, resulting in this specific complex.
Solution approach
  1. Correct Answer + Core Reason: Fe4[Fe(CN)6]3\mathrm{Fe}_4[\mathrm{Fe}(\mathrm{CN})_6]_3. This is the formula for Prussian blue.

    Step-by-Step Solution:
    Step 1: The question asks for the formula of the Prussian blue precipitate formed by the reaction of Fe3+\mathrm{Fe}^{3+} and potassium ferrocyanide.
    Step 2: Potassium ferrocyanide is K4[Fe(CN)6]\mathrm{K}_4[\mathrm{Fe}(\mathrm{CN})_6]. When it reacts with Fe3+\mathrm{Fe}^{3+}, the Prussian blue precipitate is formed, which has the formula Fe4[Fe(CN)6]3\mathrm{Fe}_4[\mathrm{Fe}(\mathrm{CN})_6]_3.

    Why other options are wrong:
    - **Option A (\mathrm{Fe}(\mathrm{H}_2 \mathrm{O})_6_2[\mathrm{Fe}(\mathrm{CN})_6]\mathrm{Fe}(\mathrm{H}_2 \mathrm{O})_6_2[\mathrm{Fe}(\mathrm{CN})_6]): This formula is incorrect for Prussian blue.
    -
    Option B (Fe2[Fe(CN)6]2\mathrm{Fe}_2[\mathrm{Fe}(\mathrm{CN})_6]_2): This formula is incorrect for Prussian blue.
    -
    Option C (Fe3[Fe(OH)2(CN)4]2\mathrm{Fe}_3[\mathrm{Fe}(\mathrm{OH})_2(\mathrm{CN})_4]_2): This formula is incorrect for Prussian blue.
    -
    Option D (Fe4[Fe(CN)6]3\mathrm{Fe}_4[\mathrm{Fe}(\mathrm{CN})_6]_3): This is the correct formula for Prussian blue.

    Key Concepts:
    - Prussian blue formation
    - Coordination chemistry

    Memory Aids:
    - Remember the formula of Prussian blue.

    Quick Tips:**
    - Recognize the reaction between Fe3+\mathrm{Fe}^{3+} and ferrocyanide ions.
23 Medium
Analyzing +4 | -1
The d−d -electron configurations of Cr2+,  Mn2+,  Fe2+\mathrm{C}{\mathrm{r}^{2 + }},\mathrm{\;M}{\mathrm{n}^{2 + }},\mathrm{\;F}{\mathrm{e}^{2 + }} and Co2+\mathrm{C}{\mathrm{o}^{2 + }} are d4,d5,d6  and  d7{d^4},{d^5},{d^6}\;and\;{d^7} respectively. Which one of the following will exhibit minimum paramagnetic behaviour?
(At. Nos.Cr=24,  Mn=25,  Fe=26,  Co=27\mathrm{Cr} = 24,\mathrm{\;Mn} = 25,\mathrm{\;Fe} = 26,\mathrm{\;Co} = 27)
View answer and explanation
Correct option: D
[Co(H2O)6]2+{\left[ {\mathrm{Co}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }}
Option D ([Co(H2O)6]2+{\left[ {\mathrm{Co}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }}) is correct because it has the least number of unpaired electrons after pairing in a weak field ligand environment.
Solution approach
  1. Correct Answer + Core Reason: [Co(H2O)6]2+{\left[ {\mathrm{Co}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }}. Minimum paramagnetic behavior is exhibited by the complex with the fewest unpaired electrons.

    Step-by-Step Solution:

    Step 1: Determine the electronic configuration of each metal ion.
    Cr2+:d4\mathrm{C}{\mathrm{r}^{2 + }}: {d^4}
    Mn2+:d5\mathrm{M}{\mathrm{n}^{2 + }}: {d^5}
    Fe2+:d6\mathrm{F}{\mathrm{e}^{2 + }}: {d^6}
    Co2+:d7\mathrm{Co}^{2 + }: {d^7}

    Step 2: Consider the ligand field strength. Water is a weak field ligand, so pairing will only occur after all the d-orbitals are singly occupied.

    Step 3: Determine the number of unpaired electrons in each complex.
    [Cr(H2O)6]2+:d4{\left[ {\mathrm{Cr}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }}: {d^4} - 4 unpaired electrons
    [Mn(H2O)6]2+:d5{\left[ {\mathrm{Mn}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }}: {d^5} - 5 unpaired electrons
    [Fe(H2O)6]2+:d6{\left[ {\mathrm{Fe}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }}: {d^6} - 4 unpaired electrons
    [Co(H2O)6]2+:d7{\left[ {\mathrm{Co}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }}: {d^7} - 3 unpaired electrons

    Step 4: The complex with the fewest unpaired electrons will exhibit the minimum paramagnetic behavior.

    Final Answer: [Co(H2O)6]2+{\left[ {\mathrm{Co}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }}

    Why other options are wrong:
    - Option A: [Cr(H2O)6]2+{\left[ {\mathrm{Cr}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }} has 4 unpaired electrons, more than the correct answer.
    - Option B: [Mn(H2O)6]2+{\left[ {\mathrm{Mn}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }} has 5 unpaired electrons, more than the correct answer.
    - Option C: [Fe(H2O)6]2+{\left[ {\mathrm{Fe}{{\left( {{\mathrm{H}_2}\mathrm{O}} \right)}_6}} \right]^{2 + }} has 4 unpaired electrons, more than the correct answer.

    Key Concepts:
    - Paramagnetism
    - d-electron configuration
    - Crystal field theory
    - Weak field ligands

    Memory Aids:
    - Hund's rule: Electrons fill orbitals singly before pairing.
    - Weak field ligands lead to high-spin complexes.

    Quick Tips:
    - Determine the number of unpaired electrons to predict paramagnetic behavior.
    - Remember the spectrochemical series to determine ligand field strength.
24 Medium
Application +4 | -1
The oxidation number of Fe\mathrm{Fe} in [Fe(CN)6]4−,Co[\mathrm{Fe}(\mathrm{CN})_6]^{4-}, \mathrm{Co} in [Co(NH3)3(NO2)3]\left[\mathrm{Co}(\mathrm{NH}_3)_3\left(\mathrm{NO}_2\right)_3\right] and Ni\mathrm{Ni} in [Ni(CO)4][\mathrm{Ni}(\mathrm{CO})_4] are respectively
View answer and explanation
Correct option: A
+2,+3,0+2,+3,0
Option A (+2, +3, 0) is correct because it accurately calculates the oxidation states of Fe, Co, and Ni in the given complexes.
Solution approach
  1. Correct Answer + Core Reason: +2, +3, 0. These are the correct oxidation states calculated for Fe, Co, and Ni respectively.

    Step-by-Step Solution:

    Step 1: Determine the oxidation state of Fe in [Fe(CN)6]4-. Let x be the oxidation state of Fe. The charge of CN- is -1. So, x + 6(-1) = -4 => x - 6 = -4 => x = +2.

    Step 2: Determine the oxidation state of Co in [Co(NH3)3(NO2)3]. Let y be the oxidation state of Co. The charge of NH3 is 0, and the charge of NO2- is -1. So, y + 3(0) + 3(-1) = 0 => y - 3 = 0 => y = +3.

    Step 3: Determine the oxidation state of Ni in [Ni(CO)4]. Let z be the oxidation state of Ni. The charge of CO is 0. So, z + 4(0) = 0 => z = 0.

    Step 4: The oxidation states are Fe(+2), Co(+3), and Ni(0).

    Why other options are wrong:
    - Option B (+3, 0, +3): Incorrect oxidation states for Fe and Co.
    - Option C (+2, +3, +4): Incorrect oxidation state for Ni.
    - Option D (0, +3, +4): Incorrect oxidation states for Fe and Ni.

    Key Concepts:
    - Oxidation state determination in coordination compounds
    - Ligand charge assignment

    Memory Aids:
    - Remember the common charges of ligands like CN-, NH3, NO2-, and CO.

    Quick Tips:
    - Always start by identifying the charges of the ligands before calculating the oxidation state of the central metal ion.
25 Medium
Understanding +4 | -1
Name the metal MM which is extracted on the basis of following reactions,
4M+8CN−+2H2O+O2→4[M(CN)2]−+4OH−4M + 8\mathrm{C}{\mathrm{N}^ - } + 2{\mathrm{H}_2}\mathrm{O} + {\mathrm{O}_2} \to 4{\left[ {M{{\left( {\mathrm{CN}} \right)}_2}} \right]^ - } + 4\mathrm{O}{\mathrm{H}^ - }
2[M(CN)2]−+Zn→[Zn(CN)4]2−+2M2{\left[ {M{{\left( {\mathrm{CN}} \right)}_2}} \right]^ - } + \mathrm{Zn} \to {\left[ {\mathrm{Zn}{{\left( {\mathrm{CN}} \right)}_4}} \right]^{2 - }} + 2M:
View answer and explanation
Correct option: B
Silver
The correct answer is B (Silver). The given reactions are characteristic of the cyanide process used for the extraction of silver from its ore.
Solution approach
  1. Correct Answer + Core Reason: Silver. The reactions describe the cyanide process for silver extraction.

    Step-by-Step Solution:

    Step 1: Analyze the given reactions. The first reaction involves the complexation of the metal with cyanide ions in the presence of oxygen and water.

    Step 2: The second reaction involves the displacement of the metal from the cyanide complex by zinc.

    Step 3: This process is commonly used for the extraction of silver and gold.

    Step 4: The reaction is: 4Ag+8CN−+2H2O+O2→4[Ag(CN)2]−+4OH−4Ag + 8CN^- + 2H_2O + O_2 \to 4[Ag(CN)_2]^- + 4OH^-
    2[Ag(CN)2]−+Zn→[Zn(CN)4]2−+2Ag2[Ag(CN)_2]^- + Zn \to [Zn(CN)_4]^{2-} + 2Ag

    Why other options are wrong:
    - Option A: Nickel: Nickel is not typically extracted using this cyanide process.
    - Option C: Copper: Copper extraction involves different methods like roasting and electrolytic refining.
    - Option D: Mercury: Mercury is extracted by heating its sulfide ore (cinnabar).

    Key Concepts:
    - Extraction of metals
    - Cyanide process
    - Complex formation
    - Displacement reactions

    Memory Aids:
    - Cyanide process is primarily used for silver and gold extraction.

    Quick Tips:
    - Remember the common extraction methods for different metals.
26 Medium
Understanding +4 | -1
Among the following pair of complexes, in which case Δ0{\Delta _0} value is higher for the second one
View answer and explanation
Correct option: C
[Co(H2O)6]+3  and  [Rh(H2O)6]+3{\left[ {Co{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}}\,\,and\,\,{\left[ {Rh{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}}
Option C ([Co(H2O)6]+3 and [Rh(H2O)6]+3{\left[ {Co{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}}\,and\,{\left[ {Rh{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}}) is correct because as we go down the group, the value of Δ0{\Delta _0} increases.
Solution approach
  1. Correct Answer + Core Reason: [Co(H2O)6]+3 and [Rh(H2O)6]+3{\left[ {Co{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}}\,and\,{\left[ {Rh{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}}. The Δ0{\Delta _0} value is higher for the second complex because Rh is below Co in the periodic table, and Δ0{\Delta _0} increases down a group.

    Step-by-Step Solution:

    Step 1: Identify the central metal ions in each pair of complexes.

    Step 2: Recall the factors affecting the crystal field splitting energy (Δ0{\Delta _0}). These include the nature of the ligands, the charge on the metal ion, and the position of the metal in the periodic table.

    Step 3: Consider the spectrochemical series for ligands. Strong field ligands cause larger splitting, while weak field ligands cause smaller splitting.

    Step 4: Consider the effect of the metal ion. For metal ions in the same group, Δ0{\Delta _0} increases down the group due to increased size and more effective overlap with the ligand orbitals.

    Step 5: Analyze each option:
    - A: [Co(NH3)6]+3{\left[ {Co{{\left( {N{H_3}} \right)}_6}} \right]^{ + 3}} and [CoF6]−3{\left[ {Co{F_6}} \right]^{ - 3}}. NH3N{H_3} is a stronger field ligand than F−F^-, so the first complex has a higher Δ0{\Delta _0}.
    - B: [Co(CN)6]−3{\left[ {Co{{\left( {CN} \right)}_6}} \right]^{ - 3}} and [Co(NH3)6]+3{\left[ {Co{{\left( {N{H_3}} \right)}_6}} \right]^{ + 3}}. CN−CN^- is a stronger field ligand than NH3N{H_3}, so the first complex has a higher Δ0{\Delta _0}.
    - C: [Co(H2O)6]+3{\left[ {Co{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}} and [Rh(H2O)6]+3{\left[ {Rh{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}}. Rh is below Co in the periodic table. Down the group, Δ0{\Delta _0} increases. Thus, the second complex has a higher Δ0{\Delta _0}.
    - D: [Co(H2O)6]+3{\left[ {Co{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}} and [Co(H2O)6]+2{\left[ {Co{{\left( {{H_2}O} \right)}_6}} \right]^{ + 2}}. Higher oxidation state leads to higher Δ0{\Delta _0}. Thus, the first complex has a higher Δ0{\Delta _0}.

    Step 6: Conclude that option C is the correct answer.

    Why other options are wrong:
    - Option A: [Co(NH3)6]+3 and [CoF6]−3{\left[ {Co{{\left( {N{H_3}} \right)}_6}} \right]^{ + 3}}\,and\,{\left[ {Co{F_6}} \right]^{ - 3}}: NH3N{H_3} is a stronger field ligand than F−F^-, so the first complex has a higher Δ0{\Delta _0}.
    - Option B: [Co(CN)6]−3 and [Co(NH3)6]+3{\left[ {Co{{\left( {CN} \right)}_6}} \right]^{ - 3}}\,and\,{\left[ {Co{{\left( {N{H_3}} \right)}_6}} \right]^{ + 3}}: CN−CN^- is a stronger field ligand than NH3N{H_3}, so the first complex has a higher Δ0{\Delta _0}.
    - Option D: [Co(H2O)6]+3 and [Co(H2O)6]+2{\left[ {Co{{\left( {{H_2}O} \right)}_6}} \right]^{ + 3}}\,and\,{\left[ {Co{{\left( {{H_2}O} \right)}_6}} \right]^{ + 2}}: Higher oxidation state leads to higher Δ0{\Delta _0}. Thus, the first complex has a higher Δ0{\Delta _0}.

    Key Concepts:
    - Crystal field splitting energy (Δ0{\Delta _0})
    - Spectrochemical series
    - Effect of metal ion charge and position on Δ0{\Delta _0}
    - Ligand field theory

    Memory Aids:
    - Strong field ligands: CO, CN−CN^-, en, NH3N{H_3}
    - Weak field ligands: H2OH_2O, F−F^-, Cl−Cl^-, I−I^-

    Quick Tips:
    - Remember the spectrochemical series to compare ligand strengths.
    - Higher oxidation state and down the group increases Δ0{\Delta _0}.
27 Medium
Analyzing +4 | -1
Which of the following does not show optical isomerism?
View answer and explanation
Correct option: C
[Co(NH3)3Cl3]0{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_3}\mathrm{C}{\mathrm{l}_3}} \right]^0}
Option C ([Co(NH3)3Cl3]0{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_3}\mathrm{C}{\mathrm{l}_3}} \right]^0}) is correct because this complex can exist as fac and mer isomers, but neither are chiral and thus do not show optical isomerism.
Solution approach
  1. Correct Answer + Core Reason: [Co(NH3)3Cl3]0{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_3}\mathrm{C}{\mathrm{l}_3}} \right]^0}. This complex exists as fac and mer isomers, neither of which are chiral.

    Step-by-Step Solution:

    Step 1: Analyze each complex for the possibility of optical isomerism.

    Step 2: Option A: [Co(en)3]3+{\left[ {\mathrm{Co}{{\left( {\mathrm{en}} \right)}_3}} \right]^{3 + }}: This complex has three bidentate ethylenediamine (en) ligands and is chiral. It exhibits optical isomerism.

    Step 3: Option B: [Co(en)2Cl2]+{\left[ {\mathrm{Co}{{\left( {\mathrm{en}} \right)}_2}\mathrm{C}{\mathrm{l}_2}} \right]^ + }: The cis isomer of this complex is chiral and exhibits optical isomerism.

    Step 4: Option C: [Co(NH3)3Cl3]0{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_3}\mathrm{C}{\mathrm{l}_3}} \right]^0}: This complex can exist as facial (fac) and meridional (mer) isomers. However, neither of these isomers is chiral, so it does not exhibit optical isomerism.

    Step 5: Option D: [Co(en)Cl2(NH3)2]+{\left[ {\mathrm{Co}\left( {\mathrm{en}} \right)\mathrm{C}{\mathrm{l}_2}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_2}} \right]^ + }: This complex can exhibit optical isomerism.

    Step 6: Final Answer: [Co(NH3)3Cl3]0{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_3}\mathrm{C}{\mathrm{l}_3}} \right]^0} does not show optical isomerism.

    Why other options are wrong:
    - Option A: Exhibits optical isomerism.
    - Option B: Exhibits optical isomerism (cis isomer).
    - Option D: Exhibits optical isomerism.

    Key Concepts:
    - Optical isomerism
    - Chirality
    - Coordination complexes
    - Facial (fac) and meridional (mer) isomers

    Memory Aids:
    - A molecule is chiral if it is non-superimposable on its mirror image.
    - fac and mer isomers are geometrical isomers.

    Quick Tips:
    - Draw the structures of the isomers and look for chirality. If the molecule is not chiral, it does not exhibit optical isomerism.
28 Medium
Analyzing +4 | -1
Assertion: In zieses salt coordination no. of PtPt is five.
Reason: Ethene is monodentate ligand.
View answer and explanation
Correct option: D
Assertion is false, Reason is true
Option D (Assertion is false, Reason is true) is correct because the coordination number of Pt in Zeise's salt is 3+1=4, and the reason correctly states that ethene is a monodentate ligand.
Solution approach
  1. Correct Answer + Core Reason: Assertion is false, Reason is true. The coordination number of Pt in Zeise's salt is 4, and ethene is considered a monodentate ligand in this context.

    Step-by-Step Solution:

    Step 1: Understand Zeise's salt. Zeise's salt is a coordination compound with the formula K[PtCl3(η2-C2H4)].

    Step 2: Determine the ligands coordinated to Pt. The ligands are three chloride ions (Cl-) and one ethene molecule (C2H4).

    Step 3: Determine the denticity of each ligand. Chloride is a monodentate ligand. Ethene (C2H4) is considered a monodentate ligand in this case, as it coordinates through its π electrons. Although both carbons are involved, it only occupies one coordination site.

    Step 4: Calculate the coordination number of Pt. The coordination number is the number of ligands directly attached to the central metal atom. In this case, it is 3 (from Cl-) + 1 (from C2H4) = 4.

    Step 5: Evaluate the assertion. The assertion states that the coordination number of Pt is five, which is false.

    Step 6: Evaluate the reason. The reason states that ethene is a monodentate ligand, which is true in this context.

    Why other options are wrong:
    - Option A (Assertion is true, Reason is true and Reason is correct explanation for Assertion): Incorrect because the assertion is false.
    - Option B (Assertion is true, Reason is true and Reason is not correct explanation for Assertion): Incorrect because the assertion is false.
    - Option C (Assertion is true, Reason is false): Incorrect because the assertion is false and the reason is true.

    Key Concepts:
    - Coordination number
    - Denticity of ligands
    - Zeise's salt

    Memory Aids:
    - Remember that ethene is considered a monodentate ligand in Zeise's salt.

    Quick Tips:
    - Carefully count the number of ligands and their denticity to determine the coordination number.
29 Medium
Remembering +4 | -1
In the lassigne’s lest for Nitrogen in an organic compound, the Prussian blue colour is obtained due to the formation of
View answer and explanation
Correct option: B
Fe4[Fe(CN)6]3F{e_4}{\left[ {Fe{{\left( {CN} \right)}_6}} \right]_3}
Option B (Fe4[Fe(CN)6]3F{e_4}{\left[ {Fe{{\left( {CN} \right)}_6}} \right]_3}) is correct because the Prussian blue color in Lassaigne's test is due to the formation of ferric ferrocyanide.
Solution approach
  1. Correct Answer + Core Reason: Fe4[Fe(CN)6]3F{e_4}{\left[ {Fe{{\left( {CN} \right)}_6}} \right]_3}. Prussian blue color is due to the formation of ferric ferrocyanide.

    Step-by-Step Solution:

    Step 1: Understand Lassaigne's test: Lassaigne's test is used to detect nitrogen, sulfur, and halogens in organic compounds.

    Step 2: Recall the reaction for nitrogen detection: In the case of nitrogen, the organic compound is fused with sodium metal to form sodium cyanide (NaCN). This NaCN reacts with ferrous sulfate (FeSO4FeSO_4) to form sodium ferrocyanide (Na4[Fe(CN)6]Na_4[Fe(CN)_6]).

    Step 3: Formation of Prussian blue: If excess iron(III) ions are present, they react with sodium ferrocyanide to form ferric ferrocyanide, which has a Prussian blue color: Fe3++[Fe(CN)6]4−→Fe4[Fe(CN)6]3Fe^{3+} + [Fe(CN)_6]^{4-} \rightarrow Fe_4[Fe(CN)_6]_3

    Why other options are wrong:
    - Option A: Na4[Fe(CN)6]N{a_4}\left[ {Fe{{\left( {CN} \right)}_6}} \right]: This is sodium ferrocyanide, an intermediate in the reaction, but not the final product responsible for the Prussian blue color.
    - Option C: Fe2[Fe(CN)6]F{e_2}\left[ {Fe{{\left( {CN} \right)}_6}} \right]: This is not the correct formula for Prussian blue.
    - Option D: Fe3[Fe(CN)6]4F{e_3}{\left[ {Fe{{\left( {CN} \right)}_6}} \right]_4}: This is not the correct formula for Prussian blue.

    Key Concepts:
    - Lassaigne's test
    - Detection of nitrogen
    - Prussian blue
    - Ferric ferrocyanide

    Memory Aids:
    - Remember that Prussian blue involves both Fe2+Fe^{2+} and Fe3+Fe^{3+} ions.

    Quick Tips:
    - Know the chemical reactions involved in qualitative analysis tests.
30 Medium
Remembering +4 | -1
The ligands in anti-cancer drug ciscis-platin are:
View answer and explanation
Correct option: A
NH3,Cl{NH}_3, {Cl}
Option A is correct. The ligands in cis-platin are ammonia (NH3NH_3) and chloride (ClCl).
Solution approach
  1. Correct Answer + Core Reason: A. NH3,Cl{NH}_3, {Cl}. Cisplatin has ammonia and chloride ligands.

    Step-by-Step Solution:

    Step 1: Recall the formula of cis-platin: cis-\PtCl_2(NH_3)_2\\PtCl_2(NH_3)_2\.

    Step 2: Identify the ligands in the formula: The ligands are NH3NH_3 (ammine) and ClCl (chloride).

    Step 3: Conclusion: The ligands in cis-platin are NH3NH_3 and ClCl.

    Why other options are wrong:
    - Option B: NH3,H2ONH_3, H_2O: Water is not a ligand in cis-platin.
    - Option C: Cl,H2OCl, H_2O: Water is not a ligand in cis-platin.
    - Option D: NO,ClNO, Cl: Nitrosyl (NO) is not a ligand in cis-platin.

    Key Concepts:
    - Coordination complexes
    - Ligands
    - Cisplatin

    Memory Aids:
    - Cisplatin: Remember the formula \PtCl_2(NH_3)_2\\PtCl_2(NH_3)_2\.

    Quick Tips:
    - Know the formulas of common coordination compounds.
Revision notes and key takeaways

Review CO-ORDINATION COMPOUNDS in your textbook or class notes, then use this set to check your understanding.

Key Takeaways

  • ✓ This set contains 133 single-correct-answer MCQs on CO-ORDINATION COMPOUNDS.
  • ✓ Try each question before opening its answer. Read the explanation where one is available.
  • ✓ Sign in to save submitted answers. Revisit incorrect answers alongside your textbook or class notes.
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