Coordination Chemistry

01

PYQ 2022

medium

chemistry ID: ap-eapce

The crystal field theory is successful in explaining which of the following?

1

I, II, III only

2

II, III, IV only

3

III, IV, V only

4

I, III, IV only

02

PYQ 2022

medium

chemistry ID: ap-eapce

The correct statements with respect to dialysis of colloidal solution are: I. Colloidal particles can pass through the membrane II. Animal bladder can be used as membrane III. Cellophane is not used as membrane IV. Ions and small molecules can diffuse through membrane into water

1

I, II only

2

II, III only

3

III, IV only

4

II, IV only

03

PYQ 2022

medium

chemistry ID: ap-eapce

Which of the following is correct related to the colours of TiCl (X) and [Ti(H O)]Cl (Y)?

1

X = Colourless,\ Y = Coloured

2

X = Coloured,\ Y = Coloured

3

X = Colourless,\ Y = Colourless

4

X = Coloured,\ Y = Colourless

04

PYQ 2022

medium

chemistry ID: ap-eapce

The homonuclear complex in the following is:

1

2

3

4

05

PYQ 2023

medium

chemistry ID: ap-eapce

The bond angle is maximum in which of the following molecules?

1

2

3

4

06

PYQ 2023

medium

chemistry ID: ap-eapce

Which of the following types of isomerism is exhibited by [Co(NH) (NO)] (NO) i. Optical ii. Linkage iii. Ionization iv. Coordination

1

ii, iii only

2

i, ii, iii only

3

i, iii only

4

ii, iv only

Official Solution

Correct Option: (1)

Step 1: Analyze the given coordination compound [Co(NH ) (NO )] (NO ) . The complex ion is [Co(NH ) (NO )] and the counter ions are 2 NO . The central metal ion is Co, with ligands 5 NH and one NO . Step 2: Check for each type of isomerism. i. Optical Isomerism: Optical isomerism occurs in chiral complexes, which are non-superimposable mirror images of each other. Octahedral complexes with at least two different types of ligands can exhibit optical isomerism if they lack a plane of symmetry. The given complex has five identical NH ligands and one NO ligand, so it is unlikely to be chiral. To be certain, consider the possible arrangements. There are no non-superimposable mirror images possible for this configuration. Thus, optical isomerism is not exhibited. ii. Linkage Isomerism: Linkage isomerism occurs when an ambidentate ligand (a ligand that can bind to the metal ion through two different atoms) is present. The nitrite ion (NO ) is an ambidentate ligand; it can bind through the nitrogen atom (-NO , nitro) or through one of the oxygen atoms (-ONO, nitrito). Therefore, this complex can exhibit linkage isomerism. iii. Ionization Isomerism: Ionization isomerism occurs when there is an exchange of ligands between the coordination sphere and the counter ion sphere. In this complex, NO is a ligand in the coordination sphere, and NO is the counter ion. An ionization isomer would involve NO as a ligand and NO as a counter ion, such as [Co(NH ) (NO )] (NO )(NO ). This is possible, so ionization isomerism is exhibited. iv. Coordination Isomerism: Coordination isomerism occurs in salts where both the cation and anion are complex ions, and there is an exchange of ligands between the two complex ions. The given compound has a complex cation and a simple anion (nitrate), so coordination isomerism is not possible. \end{itemize} Step 3: Identify the types of isomerism exhibited. The complex exhibits linkage isomerism (due to NO ) and ionization isomerism (exchange of NO and NO ). Final Answer:

07

PYQ 2023

medium

chemistry ID: ap-eapce

The compounds having coordinated water are: I. CrCl .6H O II. BaCl .2H O III. CuSO .5H O

1

II, III only

2

I, III only

3

I, II only

4

I, II, III

08

PYQ 2023

easy

chemistry ID: ap-eapce

Match the following.

1

A-IV, B-I, C-III, D-II

2

A-I, B-II, C-III, D-IV

3

A-IV, B-III, C-I, D-II

4

A-I, B-III, C-II, D-IV

Official Solution

Correct Option: (3)

09

PYQ 2023

medium

chemistry ID: ap-eapce

Which of the following statements are correct? i. both are paramagnetic ii. Both are tetrahedral and diamagnetic iii. is inner orbital complex, but is outer orbital complex

1

i only

2

i, iii only

3

ii, iii only

4

i, ii, iii

10

PYQ 2023

medium

chemistry ID: ap-eapce

The configurations of the complexes of manganese A, B respectively are t e, t e . Then A, B are:

1

[Mn(H O)], [Mn(CN)]

2

[Mn(H O)], [Mn(CN)]

3

[Mn(H O)], [Mn(CN)]

4

[Mn(H O)], [Mn(CN)]

11

PYQ 2023

medium

chemistry ID: ap-eapce

$Manganese dioxide on heating with conntrated hydrochloric acid gives a greenish yellow gas, X. With exss of ammonia X gives Y and Z. Y and Z respectively are$

1

2

3

4

Official Solution

Correct Option: (4)

$The reaction between manganese dioxide and hydrochloric acid is: So, the greenish yellow gas X is chlorine (). When excess ammonia is passed through chlorine gas, a redox reaction occurs. Chlorine reacts with ammonia as follows: In this reaction, chlorine oxidizes ammonia, producing nitrogen gas () and ammonium chloride (). Hence, the correct identities are:$

12

PYQ 2023

medium

chemistry ID: ap-eapce

$Which of the following shows the maximum number of geometrical isomers?$

1

2

3

4

Official Solution

Correct Option: (4)

$Let’s analyze the possibility of geometrical isomerism: : No geometrical isomerism due to symmetrical bidentate ligands and octahedral symmetry. Only optical isomers are possible. : Has two bidentate and two monodentate ligands; shows cis-trans isomerism. Total = 2 geometrical isomers. : Four identical and two different ligands \to cis-trans isomerism \to 2 geometrical isomers. : 3 Cl and 3 NH 3 \to shows fac-mer and cis-trans isomerism \to maximum 3 geometrical isomers. Hence, shows the maximum number of geometrical isomers.$

13

PYQ 2023

medium

chemistry ID: ap-eapce

$The IUPAC name of is:$

1

$Pentaamminechloronitrito-O-cobalt(III) chloride$

2

$Pentaamminenitrito-O-cobalt(III) chloride$

3

$Pentaamminenitrito-N-cobalt(III) chloride$

4

$Pentaammineoxonitrito-cobalt(III) chloride$

Official Solution

Correct Option: (2)

$In the complex, the ligands and central metal are: 5 groups \to pentaammine . group \to nitrito-O (oxygen-bonded form of). Central metal: Co. Oxidation state: Co is in +3 (since and ligands are neutral/anionic). So, IUPAC name becomes: Pentaamminenitrito-O-cobalt(III) chloride .$

14

PYQ 2023

medium

chemistry ID: ap-eapce

$Observe the following complexes From the above, the number of inner orbital complexes with paramagnetic nature is:$

1

$2$

2

$1$

3

$3$

4

$4$

Official Solution

Correct Option: (1)

$Inner orbital complexes involve pairing in the lower energy orbitals (low spin). Ligands like and are strong field ligands. Analyzing: - : Mn has 4 unpaired electrons, strong field \to inner orbital \to paramagnetic ✅ - : Fe, low spin \to 1 unpaired \to inner orbital \to paramagnetic ✅ - : strong field \to diamagnetic ✖ - : weak field ligand \to outer orbital ✖ - : Fe, strong field \to diamagnetic ✖ - : weak field ligand \to outer orbital ✖ Only first two are inner orbital and paramagnetic.$

15

PYQ 2024

hard

chemistry ID: ap-eapce

$Cobalt (III) chloride forms a green-colored complex ‘X’ with NH . Number of moles of AgCl formed when excess AgNO solution is added to 100 mL of 1M solution of ‘X’ is:$

1

$0.3$

2

$0.2$

3

$0.1$

4

$1$

Official Solution

Correct Option: (3)

$Step 1: Identifying the Complex - The green complex formed is Cl . - This means that for each molecule of the complex, 3 chloride ions are available for precipitation. Step 2: Moles of Complex and Cl Ions - Given: 100 mL of 1M solution Moles of complex = 0.1 moles. - Each mole of the complex releases 3 moles of Cl . Step 3: Reaction with AgNO - AgNO reacts with Cl to form AgCl precipitate: - Since each Ag reacts with one Cl , the number of moles of AgCl precipitated is 0.3 moles. Thus, the correct answer is 0.3 moles. \bigskip$

16

PYQ 2024

medium

chemistry ID: ap-eapce

$The paramagnetic complex ion which has no unpaired electrons in orbitals is$

1

2

3

4

Official Solution

Correct Option: (4)

$The problem asks us to identify a paramagnetic complex ion with no unpaired electrons in the orbitals. We will analyze each option: 1. Fe in this complex is in the +2 oxidation state, with an electron configuration of . CN⁻ is a strong field ligand and causes pairing of electrons. Thus, all six 3d electrons pair, resulting in no unpaired electrons in the orbitals. 2. Fe in this complex is in the +3 oxidation state, with an electron configuration of . Again, CN⁻ is a strong field ligand, causing most electrons to pair. However, one electron remains unpaired in the orbitals, resulting in a paramagnetic complex. 3. Zn in this complex is in the +2 oxidation state, with an electron configuration of . All d-orbitals are completely filled, so there are no unpaired electrons at all. 4. Ni in this complex is in the +2 oxidation state, with an electron configuration of . NH₃ is a weak field ligand, and does not cause pairing. Electrons fill the orbitals first, all pairing within them, leaving no unpaired electrons in these orbitals, though there are still unpaired electrons in total. Thus, while all options may have different numbers of unpaired electrons in their orbitals, the question specifically asks for no unpaired electrons in the orbitals, which is possible even in a paramagnetic complex like . Consequently, the correct choice is this complex.$

17

PYQ 2025

medium

chemistry ID: ap-eapce

$Identify the complex ion/s with the least spin only magnetic moment (in BM). I) [Fe(CN)] II) [Co(CN)] III) [Mn(CN)] IV) [Fe(CN)]$

1

$II \& IV only$

2

$I only$

3

$III only$

4

$I \& III only$

Official Solution

Correct Option: (1)

$Strong field CN ligand causes pairing of electrons in low-spin complexes. Among the given, Co in II and Fe in IV form low-spin, diamagnetic or nearly diamagnetic complexes.$

18

PYQ 2025

medium

chemistry ID: ap-eapce

$Identify the incorrect statement regarding the interstitial compounds.$

1

$They have high melting points$

2

$They lose electrical conductivity during the formation from metal$

3

$They are chemically inert$

4

$They are very hard$

Official Solution

Correct Option: (2)

$Interstitial compounds, formed when small atoms occupy the interstitial spaces in a metal lattice, typically have high melting points, are very hard, and are chemically inert. However, they do not lose electrical conductivity upon formation from metal. This statement is incorrect.$

19

PYQ 2025

medium

chemistry ID: ap-eapce

$Which of the following exhibit ionization isomerism? I) [Cr(NH) Cl]Cl II) [Ti(H O) Cl]Cl(NO) III) [Pt(en)(NH)]Cl(NO) IV) [Co(NH) (NO)]NO$

1

$II & III only$

2

$I & II only$

3

$II & IV only$

4

$III & IV only$

Official Solution

Correct Option: (1)

$Ionization isomerism occurs when two isomers differ by the exchange of ligands between the metal and the counter ion. From the given compounds, II and III exhibit ionization isomerism.$

20

PYQ 2025

medium

chemistry ID: ap-eapce

$Which of the following complexes will exhibit optical isomerism?$

1

2

3

4

Official Solution

Correct Option: (2)

$Optical isomerism occurs in coordination complexes that are chiral, i.e., they cannot be superimposed on their mirror images. - (A) : This is an octahedral complex with two chloride ligands. It can show geometrical isomerism (cis/trans) but not optical isomerism. - (B) : Here, "en" stands for ethylenediamine, a bidentate ligand. This complex has three bidentate ligands, forming an octahedral complex that is chiral. It exhibits optical isomerism (enantiomers). - (C) : Hexacyanoferrate(III) complex is octahedral but with six identical monodentate ligands. It is symmetrical and does not show optical isomerism. - (D) : This square planar complex exhibits cis-trans isomerism but no optical isomerism because square planar complexes are usually planar and symmetrical.$

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Chapter Questions
20 MCQs

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Coordination Chemistry

High-Yield Trend

Chapter Questions 20 MCQs

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Chapter Questions
20 MCQs