IGNOU BCHET-147 June 2025 Previous Year Question Paper

Q1.How are organometallic compounds classified on the basis of type of bonding ?

Q2.Explain giving examples.

Q3.Potassium ferrocyanide reacts with Zn?, Cu2+ and Fe to give characteristic precipitate/colour. Give the reactions of potassium ferrocyanide involved with each of these ions and also write the characteristic colours. Give the IUPAC nomenclature for potassium ferrocyanide.

Q4.Using the 18 electron rule as a guide, find/identify : 5

(6) The number of CO ligands in Co2(CO)n

(i) The number of metal-metal bonds in Co4(CO)12

(iii) The 3d metal in Ma(CO)s.

(iv) The charge on the complex [Fe(CO)4]*-

Q5.Draw the structure of the Zeise’s salt and explain briefly the nature of bonding in it.

Q6.Mention any three differences between hemoglobin and myoglobin. What is the role of globin chain in hemoglobin ?

Q7.Which alkaline earth metal ion is involved in blood clotting and how does it do so ?

Q8.What are the other important functions of this metal ion ?

Q9.Write the toxic effects of Pb(I]). What are the sources of lead pollution ? Give a suitable antidote for lead poisoning. 5 Part—B (Marks : 25) (Polynuclear Hydrocarbons and UV-Vis, IR Spectroscopy)

Q10.Write the reaction and its mechanism involved in the synthesis of pentane-2, 4- dione (a, ®-diketone) or butanedioic acid from ethyl-3-oxobutanoate or ethyl acetoacetate.

Q11.Find out characteristic frequencies of the following compound from given values of IR frequencies and give proper explanation for each frequency. IR frequencies given as (Gn cm"): 5 2962-2853, 3500, 3400, 3030, 1685, 1340-1250. oO CH NZ? NH,

Q12.Find out the Amax value of the following compounds : 5 @ Coe ine Given : Amax (in nm) Base value : a, B-unsaturated ketone (5-membered) = 202 nm a, B-unsaturated ketone (6-membered) = 215 nm Increments : a -substituent 10nm B -substituent 12nm y -substituent 18nm Each double bond extending conjugation 30nm Homoannular component 39nm External cyclic double bond 5nm

Q13.(a) Arrange the following molecules in their increasing order of (C = O) stretching absorption frequencies : 2 Zo | «i ay J\ Ze ay [| iw (

(b) Describe the effects of conjugation in eo 0 stretching absorption frequencies with suitable examples.

Q14.(a) Write the reaction when pyrrole is treated with maleic anhydride. 2

(b) Complete the following reactions : 3

(i) [J Na,liqNH, 9 [J 2CH,O-Nat a (J ar” N

Q15.(a) Describe Auxochrome with suitable examples. 2

(b) Give the IUPAC names of the following compounds : 3 7 ie cS ~N Br Ss a CH;

Q16.(a) Describe keto-enol tautomerization of ethyl acetoacetate. 2

(b) Find out aromatic and non-aromatic compounds among the following : 3

(iii) tJ 2962-2853, 3500, 3400, 3030, 1685, 1340-1250. Sor NH, Ci CH;

(ii) Zo A G@ (2 Gi)

(ii)

(iv) CF (i iw Na,ligNH, 9 iy (|) _2CH,O-Nat

(iii) x CHL ? Am - cH, 3 | i Br CH; w OC

(iii) [J