Course Code: BCHET-147
Assignment Code: BCHET-147/TMA/2023
Maximum Marks: 100

PART A: ORGANOMETALLICS, BIOINORGANIC CHEMISTRY

1 What is chromyl chloride test? Give suitable equations.

2 Give the suitable equations for the reaction of potassium permanganate in acidic medium with the following:
Sulphuric acid, potassium iodide, ferrous sulphate in acidic medium.

3 What is Zeise’s salt? Give suitable diagram to explain its structure.

4 Explain the structure of \(\mathrm{Fe}(\mathrm{CO})_5\) based on valence bond approach.

5 If the complex \(\mathrm{M}_2(\mathrm{CO})_9\) is obeying 18 electron rule, then identify the \(3 d\) metal in it.

6 Draw the isomers of \(\mathrm{Co}_2(\mathrm{CO})_8\) and give the differences in their structures.

7 Explain with suitable diagrams the synergic bonding in metal carbonyls.

8 Give the classification of the elements according to their occurrence in three different biological environments.

9 Give the main reactions in photosynthesis.

10 Explain the conversion of heme to hemin along with suitable diagrams.

PART B: POLYNUCLEAR HYDROCARBONS AND UV, IR SPECTROSCOPY

11 Discuss the preparation of ethyl 3-oxobutanoate starting from ethyl ethanoate. Also write the mechanism of this reaction.

12 By giving a suitable example, write the mechanism of electrophilic substitution reaction of naphthalene.

13 Which one is more basic-pyrrole or pyridine? Explain.

14 (a) Explain why nucleophilic substitution is taken place mainly and 2 and 4-positions of pyridine?

(b) Complete the following reactions:

i) Naphthalene \(\frac{\mathrm{V}_2 \mathrm{O}_5}{\Delta}\)

ii) Naphthalene \(\stackrel{\mathrm{Na}, \mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}}{\longrightarrow}\)

iii) Furan \(\stackrel{\mathrm{Br}_2}{\longrightarrow}\)

15 What are auxochromes? Give suitable examples from small organic molecules to explain this.

16 What are the two main parameters on which the characteristics of the absorption bands in ultraviolet and visible spectra depends on? Also explain in what ways the intensity of absorption can be expressed.

17 With suitable diagram give the transitions that are observed in the electronic spectra of the carbonyl chromophore.

18 Which of the following molecules absorbs at the longer wavelength?

19 Why the band for \(-\mathrm{C} \equiv \mathrm{N}\) has greater intensity than that of the \(-\mathrm{C} \equiv \mathrm{C}\) – group in the \(2500-2000\) \(\mathrm{cm}^{-1}\) region of the IR spectrum?

20 What are the main absorption bands in the IR spectra of aldehydes and ketones? Giving suitable examples, discuss the effect of conjugation on the carbonyl stretching frequency in aldehydes and ketones.