QP-IFSM-25-CHEMISTRY-PAPER-II-241125

Time Allowed : Three Hours Indian Forest Services (Main) Examination-2025 CHEMISTRY Paper - II DJSM-B-CHMY Maximum Marks : 200 Question Paper Specific Instructions Please read each of the following instructions carefully before attempting questions : There are EIGHT questions in all, out of which FIVE are to be attempted. Questions No. 1 and 5 are compulsory. Out of the remaining SIX questions, THREE are to be attempted selecting at least ONE question from each of the two Sections A and B. Attempts of questions shall be counted in sequential order. Unless struck off, attempt of a question shall be counted even if attempted partly. Any page or portion of the page left blank in the Question-cum-Answer Booklet must be clearly struck off: All questions carry equal marks. The number of marks carried by a question/part is indicated against it. Unless otherwise mentioned, symbols and notations have their usual standard meanings. Assume suitable data, if necessary, and indicate the same clearly. Neat sketches may be drawn, wherever required. Answers must be written in ENGLISH only. DJSM-B-CHMY 1. (a) (b) (c) (d) (e) (0 SECTION A Based on Huckel’s rule of aromaticity, identify the following species as aromatic, antiaromatic, and nonaromatic : |> |» ~CHg 7 - (, | | (1) (11) (111) (IV) (V) 2 9 Write the major product of the following reaction and give mechanism : N-OSO,Ar+ 6- Base,» 7 21 Giving appropriate explanation, compare the order of reactivity of pyrrole and thiophene towards an electrophile. Write the products (major/minor) in the following reaction sequence : MeO 9 Br Write the products of the following reaction and justify the stereochemical outcome with an appropriate mechanism : 1) Hg(OAc)y 2 ? ii) Write the products in the following transformations : ( qu . 0 CH,—C—C—ph - ৩১০৫ , | | cold Ph | CH3COOH/conc. 32904 ? DJSM-B-CHMY 2 (g) (h) Q2. (a) (b) (c) Indicate the products in the following sequence of reactions : 5 = 140°C 220°C B Giving the most plausible mechanism, complete the following reaction : 5 COCH3 = BOOKS - ——? (1 eqv.) Compare the rate of acetolysis of A and B giving suitable justification. Also give the roe of acetolysis in each case with mechanisms : 10 OAc ~ "Y OTs : son (B) Complete the following reaction along with the mechanism. Also indicate the product spread with suitable reasons : 10 ou BF3/Et,0 - Giving the products, complete the following reactions along with their mechanisms : 10 or xo, Br NaOH ,, mo) CH3CN DJSM-B-CHMY 3 (d) . (b) () (d) Write the products A, B and C in the following transformation indicating the processes involved and electron flow : 10 R 5 0 Write the products with mechanisms in the following reaction sequences : 10 (; - <2 ( - Ph CH30 0) ‎ 0 || :B (ii) Ph - ^ - (प - 5 - و مہہ واط - وآآن‎ 1 Write the reaction of diethyl malonate with acetaldehyde in the presence of piperidine (as catalyst). Also write the mechanism for the product(s) formation. 10 Giving mechanism, complete the following reaction : 10 0 (01003000148 PhCHO + ¬ - NH - () 0000 ? ১০১০ In the following reaction : A i) Base -----: ii) CHI A (Thermodynamically-controlled product) + B (Kinetically-controlled product) DJSM-B-CHMY 4 (1) Identify A and 3. (ii) Write a name of a base in each case to form A and B regioselectively. (iii) Write the nature of solvent and the reaction temperature required for regioselective formation of A and B. (iv) Give the mechanism of formation of A and 9. 10 4. (a) Identify the reaction from the following reactions (i ¬ iv) that shows primary kinetic isotope effect for the H-atom (€ - 11) and show the mechanism of the reaction to identify the rate limiting step : 10 1] FeCly Br 0) | | Brg H cy Heat ‎ (ii) | | >- 0 0 B H “ Balt OH 11550 (iv) _ 224 (b) Complete the following reaction with mechanism : 10 ಜಲ್ದಿ 2 Z DJSM-B-CHMY 5 (c) (i) Arrange the following compounds in order of their decreasing acidity and give suitable justification : 5 Cud I Il F3C CF; FC CF; CF, I (ii) | Complete the following reactions and give suitable explanation for the formation of the major products : 5 (d) What is/are the products obtained in a reaction when pyrrole is reacted with chloroform in aqueous basic solution ? Write the mechanism of product(s) formation. 10 DJSM-B-CHMY 6 Q5. (a) (b) (c) (d) (e) (f) SECTION B Derive the structure of the monomeric product that is identifiable by HPLC in Edman degradation of a peptide. Write the complementary base pairs in RNA and show their H-bondings by drawing the structure of the bases. Complete the following reaction and identify the electronic states involved in the reaction by showing the proper mechanism for formation of the product(s). Ph i) =O OS Ph isopropanol Write the 'H NMR spectral data of pure ethanol in anhydrous CDCly indicating approximate chemical shift values of each signal and their spin multiplicity and integration. A compound having molecular formula C4Hg0O3 gives the following mass fragments. Deduce the fragmentation pattern to identify the mass peaks and the base peak. m/z = 102, 60, 43, 42, 15. An organic compound with molecular formula C19H 209 exhibits the following spectral data : IR (em~!) : 3100, 2944, 2856, 1690, 1100 cm“! 14H NMR (CDClg) : 6 7-80 (2H, d, J = 8 Hz), 6-80 (2H, d, J = 8 Hz), 4-10 (2H, q, J = 7-2 Hz), 2-4 (3H, s), 1-25 (3H, t, J = 7-2 Hz) Mass : m/z 164, 121, 48, 15. Derive the structure of the compound and assign all the data. DJSM-B-CHMY 7 15 Q6. (a) Write the products formed in the following reactions and give suitable mechanism/explanation. (i) (ii) hv o ——? O Ph IO “ ? Ph = hy (b) (i (ii) () @ (ii) Q7. (a Wi) (ii) DJSM-B-CHMY Write approximate 1H NMR chemical shift values and multiplicity of each signal to differentiate between ethyl acetate and methyl propionate. A compound having molecular formula C ,H 9904 gives the following 1H NMR data. Identify the compound and assign the protons. 5x 3= 15 5 TH NMR (CDCl3, 300 MHz) : 6 4-18 (q), 1-92 (t), 1:24 (q), 0-82 (t) ppm. What will be the number average and weight average molecular weight of a sample of propylene oligomer that consists of 5 mol of pentamer and 10 mol of hexamer ? Mention the product of the given reactions with proper mechanism : OsO, MCPBA B HO H,0 . HClO, Propose the chemical reaction for synthesis of polyphosphonitrilic chloride. The freshly prepared polyphosphonitric chlorides are soluble in chloroform but insoluble in petroleum. Why ? Propose the mechanism for synthesis of silicones from dialkyl dichlorosilane. How is chain branching introduced in silicones ? 8 10 10 10 Calculate the ultraviolet absorption maxima of substituted dienes (b) @ using Woodward-Fieser rules : CgHy7 4 (I) AcO “ CO Deduce the Amax values in given a-f-unsaturated carbonyl ColHi9 (ii) compounds using Woodward-Fieser rules : O R oO DJSM-B-CHMY (6) | Write down the major product of the following reactions : (II) (111) (117) () . (5) (i) (ii) 00) 0) DJSM-B-CHMY XN (1) NBS (2) 30% NaOH CrO3 --- ‎ HCl N CHO NaBH EtOH (1) 8014 Sa ns 10५ ہہ وروی‎ 7 0 5602 =... = = (1 equiv.) Deduce the rotational constant and C = O bond length in carbon monoxide when the first line in the rotational spectrum has a frequency 083-8424 1. Given : Avogadro number = 6-022 x 1023 1 = 6-625 x 10-27 cm? g/s; = 3 x 1010 em/s Calculate the change in the rotational constant, when hydrogen is replaced by deuterium in the hydrogen molecule. Calculate the change in energy for a given reaction : HCl + 109 , DCl+ HD Given the frequencies of vibration of the molecules at v = 0, HCl = 2885 , Dy = 2990 1, 201 = 1990 ‌! and HD = 3627 , h = 6-625 x 10 34 m2 kg/s, 3 x 108 m/s. 10 10 10 10 (1) What will be the intensity of the hot band 1' = 1 -> = 2 relative to the fundamental 1' = 0 -» = 1 10 Iodine molecule at temperature 300 ? Given : Equilibrium vibration frequency of Iodine molecule = 215 . Anharmonicity constant x, = 00038. 3 × 108 m/s; h = 6-625 x 10-34 112 (‎ 10 (6) Despite the lower electronegativity of sulphur, thiophene metallates as readily as furan. Why ? 5 DJSM-B-CHMY 11