IGNOU BCHET-147 December 2025 Previous Year Question Paper

Q1.What are the reduction products of KMnOs in

(i) Acidic medium,

(ii) Alkaline medium, and

(iii) Neutral medium ? Find the oxidation state of manganese and KMnO. and all the above reduction products.

Q2.Explain why the transition metal organometallic compounds have immense variety in their structure and bonding types.

Q3.Why are organometallic compounds good catalysts in chemical industry ? 5 C-2721] BCHET-147 What are the two possible structures of ferrocene ? Draw the structures for both and give two differences.

Q4.“All Ni-C bond lengths in Ni(CO)s are identical but Fe—C bond lengths in Fe(CO)s are not identical.” Explain this statement with respect to valence bond approach and give the structures for both.

Q5.How will you classify the elements on the basis of mechanism of action in biological systems ? Give suitable examples of each class.

Q6.What purpose does magnesium serve in the process of photosynthesis ? Give the net reaction in photosynthesis.

Q7.Which heavy metal was responsible for Itai-Itai disease in Japan ? What was the source of the disease ? Name two antidotes for the above metal.

Q8.Which metal is present in hemoglobin and myoglobin ? Give four differences between them. 5 Part—B (Marks : 25) (Polynuclear Hydrocarbons and UV-Vis, IR Spectroscopy)

Q9.(a) What are active methylene compounds ? Explain keto-enol tautomerization. 3

(b) Explain Claisen ester condensation for the synthesis of any 3-oxo-esters. 2 C-2721]

Q10.(a) Give the IUPAC name of the following compounds : 3 NOs 170५ CHs ae ८7 \ Gii) ¢ YN

(b) Assign [A] and [B] in the following reaction with their names : 2 V205 A A B (O10) ~ a 7B,

Q11.(a) Give the reaction when maleic anhydride reacts with pyrrole and furan. 3

(b) Explain the properties of polycyclic aromatic hydrocarbons.

Q12.(a) Explain various electronic transitions involved in UV _ spectroscopy with suitable example from a small organic molecule. 3

(b) Explain Beer-Lambert’s law of absorption.

Q13.(a) Assign the stretching frequencies for a particular functional group in the given compound : 3 "Cree C=C—H C-2721] BCHET-147 IR stretching frequencies (in cm~) :

Q14.3400, 3309, 3040, 2960-2851,

Q15.1720

(b) Which molecule will absorb at longer wavelength ? Explain :

Q16.(a) Explain normal modes of vibrations for a polyatomic molecule. 3

(b) Arrange the following functional groups in increasing order of their (C = O) stretching absorption frequenices : 2

(6) Acid chlorides Gi) Esters

(iii) Amides

(iv) Anhydrides

Q17.(a) Complete the following reactions and assign [A], [B] and [C] along with their names : 3 . Bro

Q18.© ox” ATE 803 ai) l\ \ Pyridine (¢]

(b) Write a reaction when ethyl-3-oxo- butanoate is treated with chloropropanone in presence of pyridine and also name the product formed. 2 C-2721] BCHET-147 stated Bae fren) NO, CH3 Gi) 7 py H2N cr CH; C=C—H

Q19.3400, 3309, 3040, 2960-2851,

Q20.1720 €1 [क] fal

(ii) TR

(iii) THES Bro

Q21.[0] sa lt el CYS Fa”