BCHET-147 · December 2022 · English
IGNOU BCHET-147 December 2022 Previous Year Question Paper
Organometallics, Bioinorganic Chemistry, Polynuclear Hydrocarbons And Uv-Vis, Ir Spectroscopy
Structured previous year question paper for BCHET-147, December 2022 session.
Max marks: 50 · Questions: 14
Verified: 29 Jul 2026
BACHELOR OF SCIENCE (GENERAL)
(BSCG)
Term-End Examination
December, 2022
BCHET-147 :ORGANOMETALLES,
BD NORGANE CHEM SBTRY,POLYNUCLEAR
HYDROCARBONS AND UVV5B,R
SPECTROSCOPY
Time : 2 Hours Maximum Marks : 50
Note :
(i) Attempt any five questions from Part A
and any five questions from Part B on
separate answer sheets.
(ii) All questions carry equal marks.
Part—A (Marks : 25)
Q1.(a) With suitable equation, give the reaction as well as change in colour when dilute alkali is added to potassium dichromate. 3
(b) Write any two uses of potassium permanganate and give its IUPAC name.
Q2.How are sigma bonded organometallics formed ? Give suitable examples of each of these compounds. Why do these compounds when formed with transition metals become unstable ?
Q3.What are the general methods of preparation of simple carbonyls ? Give any one reaction for each.
Q4.Explain synergic bonding in metal carbonyls with suitable diagrams.
Q5.(a) What are essential trace elements ? When are they called ultra-trace elements ? Give two examples of each. 4
(b) Why is arsenic toxic ?
Q6.(a) Give the utility of magnesium ions in the process of photosynthesis. 3
(b) What is Chlorophyll ? How does it help in photosynthesis ?
Q7.Explain the Perutz mechanism in the context of oxygenation of hemoglobin. 5 Part—B (Marks : 25)
Q8.How will you synthesize 6-hepten-2-one starting from ethyl 3-oxobutanoate ? Write the sequence of the reactions involved and the required reagents.
Q9.(a) Explain Huckel’s rule using naphthalene and anthracene as examples. 3
(b) What are the different types of polynuclear aromatic hydrocarbons ? Give one example of each.
Q10.(a) Discuss the mechanism of sulphonation of pyrrole giving the resonance structures of the carbocation formed. 3
(b) Draw and explain the orbital structure of pyridine.
Q11.Give the schematic diagram of the order of molecular orbital energies and the possible electronic transitions (for small organic molecules). Arrange these transitions in the increasing order of their energies.
Q12.(a) Arrange 4,,, value for x—-x° transition in increasing order of the 1, 3-butadiene, 1, 5-hexadiene and 1, 3, 5-hexatriene. Justify your answer. 3
(b) Of the two compounds mesitylene (1, 3, 5-trimethylbenzene) and benzene, which would have higher i,,,, value ? Justify your answer.
Q13.Calculate the vibrational degrees of freedom of CO,,H,O and NH; molecules.
Q14.(a) Write the ranges of IR absorption bands for various vibrations exhibited by alkenes. 3
(b) Do the C-H stretching vibrations in alkanes and alkenes appear in the same region of IR spectrum ? Explain giving suitable reason. 2 feet ara eat sik a ‘a’ से fret a?