IGNOU MCH 11 SOLVED ASSIGNMENT

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MCH 11 2025 - English

Tutor Marked Assignment

MCH-011: INORGANIC CHEMISTRY 1

Course Code: MCH-011

Assignment Code: MCH-011/TMA/2025

Maximum Marks: 100

Note: Attempt all questions. The marks for each question are indicated against it.

1. a) Give the trends in metallic radii of alkali, alkaline earth and transition metals of fourth, fifth and sixth periods with proper illustration.

b) Explain periodic variation of electronegativity with atomic number for the first six rows of the periodic table.

2. a) What are the possible molecular structures of xenon hexafluoride? Explain with suitable figures. Explain the geometrical isomers of Ma₂b₂cd complex with suitable figures.

b) With suitable illustration explain the theory of Craig and Paddock for a bonding in phosphazenes. Give some synthetic routes for polyphosphazenes.

3. a) Explain the concept of hapticity giving suitable examples.

b) What is ẞ-elimination in organometallic chemistry? What is the role of agnostic alkyls in ẞ-elimination?

4. a) With suitable examples explain fluxional organometallic compounds. What are the probable of symmetric and semibridging carbonyls. Give suitable examples.

b) Determine the number and symmetry designations of the infrared-active C-O modes in the following derivatives of Mo(CO)_6-

Mo(CO)₅PR₃

cis-Mo(CO)₄ (PR₃)₂

trans-MO(CO)₄ (PR₃)₂

fac-Mo(CO)₃ (PR3)₃

5. a) With the help of molecular orbital theory explain the geometry of the nitrosyl ligand.

b) What are the polydentate phosphines? How do you prepare molybdenocene.

6. a) Give the structures of (a) B₇H^2-₇; (b) B₅H^4-₅

b) What are Wade's Rule? Apply them to any metalloborane.

7. a) Explain the different types of compounds having multiple metal-metal bonds.

b) If pairing energy P for Fe³⁺ ion is 29,875 cm^-1 and for [Fe (H₂O)₆]³⁺ is 13,700 cm^-1, find out

(i) whether the complex is high spin or low spin

(ii) the number of unpaired electrons

(iii) whether the complex is coloured or not?

8. a) Give the octahedral as well as tetrahedral field electronic configuration for Cr³⁺and Co³⁺ ions. Which site will be preferred by these ions, octahedral or tetrahedral? Justify your answer.

b) Explain the Curie Law and Curie-Weiss Law along with their plots.

9. a) With suitable illustration explain the super exchange mechanism in d-metal complexes.

b) Write the Russell-Saunders terms symbols for states with the angular momentum quantum numbers (L,S) (a) , (b) , (c) .(d) 

10. a) [FeF] is almost colourless whereas [CoF₆]^3- is coloured and exhibits only a single band in the visible region of the spectrum. Justify.

b) Explain charge transfer spectra with suitable examples. What is the reason for the deep purple colour of the permanganate ion?

MCH 11 2025 2026 - English

Tutor Marked Assignment

MCH-011: INORGANIC CHEMISTRY 1

Course Code: MCH-011

Assignment Code: MCH-011/TMA/2025-26

Maximum Marks: 100

Note: Attempt all questions. The marks for each question are indicated against it.

1.

a) Explain the trends of ionization energy down the groups of the elements in the periodic table. How are the higher values of ionisation energies of the 5d transition elements justified?

b) What is the trend of the stability of the +6 state for Group 6 elements like tungsten, molybdenum and chromium? Which other group show a similar trend? Justify your answer.

2.

a) Explain the structure of the pentafluorotellurate(IV) anion with the help of VSEPR theory. What is the point group of the symmetry in it?

b) With suitable illustration explain the theory of Dewar for π bonding in phosphazenes. What is phospham and how it is synthesized? Give suitable reaction.

3.

a) Give the classification of nonclassically bonded organometallic compounds.

b) With any two suitable examples show how organanometallic complexes of different classes may be stabilized by bulky ligands.

4.

a) With suitable illustration explain the bent tin-tin double bond in (SnR2)2; where R = (Me3Si)2CH.

b) With the help of suitable examples and structures, explain why some of the 16-electron organometallic complexes are stable. For a dⁿ metal ion which form will be more stable, 16-electron square planar complex (d⁸ and 8 ligand electrons) or a 18-electron complex (d⁸ and 10 ligand electrons)? Justify your answer.

5.

a) With suitable diagrams explain the electronic structure of NO and its binding to a metal fragment on the covalent model.

b) Compare the characteristics of electron-rich phosphines with those of electron poor phosphines regarding their σ donor and π acceptor capacities. What happens to these characteristics when the average electronegativity of the three groups attached to P increases?

6.

a) Explain the π system of the allyl group with the help of molecular orbital theory. Illustrate your answer.

b) Give the structure of titanocene with its IUPAC nomenclature. How is the Hund's rule obeyed in manganocene?

7.

a) Give the reactions for preparation of decaborane(14) from B₅H₈⁻ anion. Which is the only neutral dodecaborane and how is it prepared? Give suitable equation.

b) Explain the structure of MoCl₄²⁻. Which are the two main classes of metal atom cluster compounds?

8.

a) Give the electronic configuration of d⁸ and d⁹ complexes in both weak and strong fields. Also calculate their CFSE.

b) Explain the structure of normal spinels with a suitable example. Give suitable illustration.

9.

a) Give suitable equations and explain the orbital and spin contributions towards paramagnetism in a complex.

b) What is the expected magnetic moment of the complex MnF₃? What sort of stereochemistry is seen in it? What is the electron configuration in it based on crystal field theory.

10.

a) Write the Russell-Saunders terms symbols for states with the angular momentum quantum numbers (L,S) (a) (1, 1/2) (b) (2,1) (c) (0, 3/2) (d) (3, 0).

b) Explain how the R- and S- labels are used for enantiomers. Explain the λ and δ conformations of methyl axial and methyl equatorial respectively. Give suitable illustrations for all of these.

MCH 011 (July 2026 - January 2027) - ENGLISH

Tutor Marked Assignment
MCH-011: INORGANIC CHEMISTRY 1
Course Code: MCH-011
 Assignment Code: MCH-011/TMA/2026-27
Maximum Marks: 100
Note: Attempt all questions. The marks for each question are indicated against it.
1. a) Explain the trends in melting points of alkali, alkaline earth and transition metals of
fourth, fifth and sixth periods along with suitable illustration.
(5)
 b) Give the second postulate of VSEPR theory. Predict at the structure of the molecule
sulfur tetrafluoride with the help of VSEPR theory. Draw the structure.
(5)
2. a) Which ones of the following species will exhibit inorganic aromaticity:
a) S N b) S N c) S N 3 3 4 5 3 5
  ? Justify your answer.
(5)
 b) With the help of suitable chemical equations explain how the mixed-substituent
polymers of phosphazenes are synthesized?
(5)
3. a) Give the classification of organotransition metal alkyls and aryls along with suitable
examples for each type.
(5)
 b) With the help of a suitable example explain what fluxional organanometallic
compounds are. With the help of NMR studies how their presence was confirmed?
(5)
4. a) Calculate the Effective Atomic Number (EAN) of the Mn(CO)4NO complex. Here how is the
ligand NO treated as? In this was how the ligand NO becomes analogous to CO and N2?
(5)
 b) With the help of suitable diagrams, explain the synergic bonding in metal carbonyls. (5)
5. a) Which metals form dinitrogen complexes? Which other ligands can coexist in a
nitrogen metal complex? Give any two examples of such complexes are prepared by
using nitrogen gas directly. Give suitable chemical equations.
(5)
 b) How are dioxygen adducts of cobaltocenes prepared? (5)
6. a) Give an example of a transition metal-dinitrogen complex. Give suitable chemical equation for
its preparation. In what fashion can the two metal atoms be bridged by dinitrogen? What
happens when the dinitrogen ligands bind in side-on mode? Gives suitable diagrams.
(5)
 b) With the help of suitable diagram explain the Tolman cone angle in phosphines. (5)
7. a) Give a suitable chemical equation for the preparation of molybdenocene. Gives its reaction with
ethylene.
(5)
 b) What are heterocarboranes? Which elements are involved in it? With suitable equation give the
preparation of any one multidecker metal sandwich complexes.
(5)
8. a) What is Jahn Teller effect? As a manifestation of it show why high-spin d
4
 (e.g., Cr2+) and lowspin d7
 six-coordinate complexes (e.g. Co2+) may show distortion. 

b) Give the octahedral as well as tetrahedral field electronic configuration for the Cr3+ and Mn2+
ions. Which site will be preferred by these ions, octahedral or tetrahedral? Justify your answer.
(5)
9. a) With the help of a suitable diagram explain the trend of paramagnetic moments of La3+ and the
lanthanoid ions at 300K. Why is the chance of superexchange interaction less in lanthanoid
complexes?
(5)
 b) With a suitable example explain intermolecular antiferromagnetism. Give its mechanism for the
case of direct metal-metal interaction. Give suitable illustrations.
(5)
10. a) What are Racah parameters? What do they signify? The gas-phase ion V3+ has a 3F ground
term. The 1D and 3P terms lie, respectively, 10,642 and 12,920 cm-1 above it. The energies of
the terms are given in terms of Racah parameters as E(
3F) = A=8B, E(
3P)=A+7B, E(
1D) =
A-3B+2C. Calculate the values of B and C for V
3+
.
(5)
 b) What is meant by the octant sign? How can you follow the octant rule to determine the absolute
configuration of cyclic ketones? How do we confirm whether a complex is ∆-isomer or
˄-isomer? 

 

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