IGNOU BCHCT-137 Solved Assignment 2026 (January & July 2026) – BSCM – English Medium PDF

📌 Programme: BSCM (B.Sc. Major) · Course: BCHCT-137 — Coordination Chemistry, States of Matter and Chemical Kinetics · Session: January 2026 & July 2026 · Last date: 30 Apr 2026 (Jan 2026) / 31 Oct 2026 (Jul 2026), as per IGNOU portal.

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IGNOU BCHCT-137 assignment (January 2026 & July 2026) ke ye sawaal is PDF mein solved hain:

1. Q1. Give the name and symbols for the elements that have the following valence configurations.
   i) 4s13d5 ii) 5s24d5 iii) 5s24d10 iv) 5s14d8 v) 4s13d10 vi) 5s14d4 5 marks
2. Q2. In [Cu(H 2O)6]2+ the observed magnetic moment is higher than the spin-only value. Explain the reason for this in the space provided below. 5 marks
3. Q3. What is the general pattern of electronic configuration of the lanthanoids? Give the three exceptions to this. 5 marks
4. Q4. Determine the coordination number and the oxidation state of the transition metal ion in each of the following complexes: (a) [Co(NH3)6]³⁺ (b) [CuCl4]²⁻ (c) [Cu(NH3)4]Cl2 (d) K2[PtCl6] 5 marks
5. Q5. Explain why Co(III)–NO 2 (nitro) complexes slowly convert into Co(III)–ONO (nitrito) complexes or vice versa. 5 marks
6. Q6. According to valence bond theory, how do you account for the indicated molecular geometry for the following compounds:
   (i) [Co(NH3)6]3+ - Octahedral and (ii) [ZnCl4]2- - Tetrahedral 5 marks
7. Q7. Explain polymerization ligand isomerism with suitable example. 5 marks
8. Q8. What would be the CFSE for an octahedral complex of a d6 ion in weak field and strong field? 5 marks
9. Q9. Six-coordinate d9 complexes of copper (+2) show pronounced tetragonal distortions. High-spin d4 (e.g., Cr2+ and Mn3+ and low-spin d7 six-coordinate complexes (e.g. Co2+ and Ni3+) may show a similar distortion, but complexes of these ions are less common, and the distortions are less pronounced than those in copper (+2). Why? 5 marks
10. Q10. Determine how many unpaired electrons are contained in the following octahedral complex ions: 3-[ C o ( C N ) ]6 , 3-[ C o F ]6 Estimate the magnetic moments of these complexes. 5 marks
11. Q11. a) How many molecules of oxygen are present in 0.0032 kg of the gas?
    b) Calculate the temperature at which the root mean square velocity, the average velocity and the most probable velocity of the oxygen gas are all equal to 1500 ms−1. 5 marks
12. Q12. Calculate the pressure of 3.000 mol of methane at 298.2 K using the other data from the above illustration and assuming that it obeys van der Waals equation. Also calculate its value, if methane were to behave ideally at 298.2 K. [Note: the illustration data (volume, van der Waals constants) is not printed in the assignment booklet; the solution uses standard textbook constants for methane and a clearly stated assumed volume to demonstrate the method.] 5 marks
13. Q13. What is meant by total attractive interaction energy in molecules? Explain the factors that influence its magnitude. 5 marks
14. Q14. With suitable diagrams, explain the plane of symmetry in a cubic system. 5 marks
15. Q15. Explain the seven primitive unit cells in crystals. Give suitable diagrams. 5 marks
16. Q16. The density and cell-edge length of potassium chloride (KCl) are 1.99 × 10³ kg m⁻³ and 6.29 × 10⁻¹⁰ m, respectively. Using these data, determine the number of formula units per unit cell of potassium chloride crystal. 5 marks
17. Q17. a) In the decomposition reaction of hydrogen iodide, given below 2HI (g) → H2(g) + I2 (g) find out the relationship between the rate of reaction in terms of decomposition of HI and in terms of formation of H2 (g).
    b) Give the factors affecting the rate of a reaction. How do catalyst affect the rate of the reaction? 5 marks
18. Q18. a) What is the effect of pressure and temperature on the viscosity of gases? Explain briefly.
    b) What are the differences in the behaviour of real and ideal gases? Derive the expression for the critical temperature of a van der Waals gas. 5 marks
19. Q19. a) Write the differential rate equations for the following reactions, assuming them to be elementary reactions: i) 2A + 5B → 3C + 2D + E ii) A + 2B → 3C
    b) Azomethane (CH3)2N2 decomposes with first order kinetics according to the equation (CH3)2N2(g) → N2(g) + C2H6(g). The following data were obtained for the decomposition in a 200 ml flask at 300 °C. Time (t) in min: 0, 15, 30, 48, 95; Total pressure, torr: 36.2, 42.4, 46.5, 53.1, 59.3. Calculate the rate constant and the half-life for this reaction. 5 marks
20. Q20. a) Calculate the activation energy of a reaction whose rate constant is tripled by a 10 °C rise in temperature in the vicinity of 32°C.
    b) Discuss the activated complex theory of biomolecular reactions. Explain how this theory helps in evaluating standard enthalpy of activation and standard entropy of activation. 5 marks

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