2005 CH 1 1. Presents IIT JAM PAPER 2005 C H E M I S T R Y

Transcription

1 005 CH 1 1 E i n s t e i n C l a s s e s Presents IIT JAM PAPER 005 C H E M I S T R Y

2 NOTE : CHEMISTRY PAPER CH Attempt All the 44 questions. Questions 1 30 (objective questions) carry three marks each and questions (subjective questions) carry fifteen marks each. Write the answers to the objective questions ONLY in the Answer Table for Objective Questions provided on page Arrange the following in the decreasing order of acidity of the hydrogen indicated in italics. (i) CH 3 COCH 3 (ii) CH 3 COCH COCH 3 (iii) CH 3 OOCCH COOCH 3 (iv) CH 3 COCH NO (ii) > (iii) > (i) > (iv) (iv) > (ii) > (iii) > (i) (iv) > (iii) > (ii) > (i) (d) (ii) > (iv) > (iii) > (i). For the reaction shown below if the concentration of KCN is increased four times, the rate of the reaction will be MeOH aq. doubled increased four times unaffected (d) halved 3. Benzyl chloride is reacted with different nucleophiles shown below. Arrange them in the decreasing order of reactivity. Nucleophiles : (d) 4. The rate of nitration of the following aromatic compounds decreases in the order (i) benzene (ii) pyridine (iii) triolphene (iv) toluene (iv) > (i) > (iii) > (ii) (iii) > (iv) > (i) > (ii) (iii) > (ii) > (i) > (iv) (d) (ii) > (i) > (iv) > (iii)

3 005 CH 3 5. The major product formed in the reaction of 1, 3-butadiene with bromine is BrCH CH(Br)CH = CH CH = CH CH CH Br CH = C(Br) C(Br) = CH (d) BrCH CH = CHCH Br 6. The reaction of (+) -iodobutane and NaI* (I* is radioactive isotope of iodine) in acetone was studied by measuring the rate of racemization (k r ) and the rate of incorporation of I* (k i ). (+) CH 3 CH(I)CH CH 3 + NaI* CH 3 CH(I*)CH CH 3 + NaI For this reaction, the relationship between k r and k i is k i = k r k i = (1/) k r k i = k r (d) k i = (1/3) k r 3 7. In the scheme shown above (P), (Q), (R) and (S) are (P) = purine bases, (Q) pyrimidine bases, (R) = nucleotides, (S) = nicleosides (P) = (Q) = nucleotides, (R) = pyrimidine bases, (S) = purine bases (P) = nucleosides, (Q) = nucleotides, (R) = (S) = purine bases (d) (P) = nucleotides, (Q) = nucleosides, (R) = pyrimidine bases, (S) = purine bases 8. The product obtained from the following reaction are H + C H 5 OH + C H 5 OH + C H 5 18 OH (d) + C H 5 18 OH

4 4 9. The product(s) obtained in the following reaction is (are) 005 CH 4 D (d) 10. Match the isoelectric points with the amino acids Amino acid Isoelectric point (X) H NCH COOH (I) 9.5 (Y) HOOCCHCHCH(NH)COOH (II) 6.0 (Z) H N(CH ) 4 CH(NH )COOH (III) 3.1 (X) (II), (Y) (III), (Z) (I) (X) (III), (Y) (I), (Z) (II) (X) (I), (Y) (II), (Z) (III) (d) (X) (II), (Y) (I), (Z) (III) 11. The compound having the highest melting point is LiCl LiF LiI (d) LiBr 1. The shape of SF 4 is tetrahedral trigonal bipyramidal square planar (d) octahedral 13. The degree of hydration is expected to the maximum for Mg + Na + Ba + (d) K +

5 005 CH The decreasing order of the first ionization energy of the following elements is Xe > Be > As > Al Xe > As > Al > Be Xe > As > Be > Al (d) Xe > Be > Al > As 15. The radioactive isotope used to locate brain tumors is D 7 N 53 I (d) 6 C 16. The crystal field stabilization energy of high spin d 7 octahedral complex is 4 P P P 5 0 (d) 9 3P The complex with the most intense colour among the following is [FeF 6 ] 3 [MnCl 4 ] [CoCl 4 ] (d) [CoF 6 ] On addition of a solution of AgNO 3 to a solution of Na S O 3, it turns black on standing due to the formation of Ag Ag S Ag S O 3 (d) Ag SO Among the following complexes, (i) [Ru(bipyridyl) 3 ] + (ii) [Cr(EDTA)] (iii) trans [CrCl (oxalate) ] 3 (iv) cis [CrCl (oxalate) ] 3 the ones that show chirality are (i), (ii), (iv) (i), (ii), (iii) (ii), (iii), (iv) (d) (i), (iii), (iv) 0. The electronic configurations that have orbital angular momentum contribution in an octahedral environment are d 1 and high spin d 4 d 1 and d d and high spin d 6 (d) high spin d 4 and high spin d 6 1. For an ideal solution formed by mixing of pure liquids A and B H mixing = 0 H mixing < 0 H mixing > 0 (d) S mixing = 0

6 6. The relationship between the equilibrium constant K 1 for the reaction : 005 CH 6 CO(g) + ½ O (g) CO (g) and the equilibrium constant K for the reaction : CO(g) + O (g) CO (g) is K 1 = K K 1 = K K 1 = K (d) K 1 = K 3. For H-like atoms, the ground state energy is proportional to µ Z Z 1 µz µ (d) µz where µ is the reduced mass and Z is the nuclear charge. 4. The value of the integral x e x dx is x e x + xe x + e x 1 x x (x e xe e x ) 1 x x x (x e xe e ) (d) x e x xe x e x 5. For the reaction aa products, the plot of order of the reaction is 1 versus time (t) gives a straight line. The [A] 0 1 (d) 3 6. The ph of a solution prepared from mole of Ba(OH) in 100 cc water is (d) For an electron whose x-positional uncertainty is m, the uncertainly in the x- component of the velocity in ms 1 will be of the order of (Data : m e = kg, h = Js) (d) For the following system in equilibrium CaCO 3 (s) CaO(s) + CO (g) the number of compounds (C), phases (P) and degree of freedom (F), respectively, are,, 1, 3, 0 3, 3, (d), 3, 1

7 005 CH For the distribution of molecular velocities of gases, identify the correct order from the following (where v mp, v av and v rms are the most probable velocity, average velocity and root mean square velocity, respectively) v rms > v av > v mp v mp > v rms > v av v av > v rms > v mp (d) v mp > v av > v rms 30. Given that E 0 Fe 0.44V and E V, the E is / Fe 0 Fe / Fe 0 Fe / Fe 1.1 V 0.33 V V (d) V 31. Identify the major product(s) formed in the following reactions. Intermediates and reaction mechanisms need not be discussed. 1.NHOH.HCl.H SO / 4 [6] NaOEt [6] 1.HNO / H SO [3] 3 4.H3O / 3. How may the following transformations be affected? Indicate the reagents / reaction conditions clearly in each step. (not involving any functional group transformations of the COOH group in the starting material) [6] (using diethyl malnoate as the only source of carbon) [3] [6]

8 8 33. Suggest a suitable mechanism for each of the following reactions. 005 CH 8 PhCOCH CH 3 + Ph C C COOEt NaOEt [6] EtOH HCl [9] 34. Rationalize the following observations using suitable mechanisms. Nitration of 4-t-butyltoluene gives 4-nitrotoluene as one of the products. [3] cis-4-t-butylclohexyltrimethylammonium hydroxide undergoes Hoffman elimination to yield 4-t-butylcyclohexene whereas the trans isomer does not (use conformations to explain). [6] PhMgBr + PhCHO 1.dryether.acidic workup PhCOPh + PhCH OH [6] 35. Suggest a chemical method for the separation of a mixture containing p-n, N-dimethylaminophenol and p-aminobenzoic acid and give a confimatory test for phenol. [6] Write the structures of X, Y and Z in the following. 1.NaNO / dil.hcl,0 C (i) X. naphthol/ NaOH 0 / dil.hcl (ii) NaNO Y / dil.hcl (iii) NaNO Z [9] 36. Predict the hybridization and draw the structure of the following molecules based on VSEPR theory : (i) I 3 (ii) SO 3 (iii) P(CH 3 ) 3 F [9] Explain why PCl 5 exists and PH 5 does not. [6] 37. Write balanced equation for the formation of (i) PO from PO (ii) [(H O) 4 Fe(OH) Fe(OH) ) 4 ] 4+ from [Fe(OH ) 6 ] 3+ [6]

9 005 CH 9 Which one of the two solutions has lower ph? Justify your answer. 9 (i) 0.1 M Fe(ClO 4 ) or 0.1 M Fe(ClO 4 ) 3 (ii) 0.1 M Hg(NO 3 ) or 0.1 M Zn(NO 3 ) [9] 38. Between Cu(H O 6 ) + and Co(H O) 6 +, which one has more distorted structure and why? [6] Calculate CFSE (in units is 0 ) and spin only magnetic moment for the following complexes. (i) [CoF 6 ] 3 (ii) [Fe(CN) 6 ] 3 (iii) [NiCl 4 ] [9] 39. The radioactive element Ra (Z = 88) emits three alpha particles in succession. Deduce in which group the resulting element will be found? [6] A radioisotope sample has an initial activity of 3 dis/min. After ½ h, the activity is 11.5 dis/min. How many atoms of the radioactive nuclide were present originally? [t ½ = 0.69] [9] 40. Write the products of the following reactions : (i) (ii) CH 3 I + HO CF 3 I + HO (iii) 41. Justify the following : (d) (e) CF 3 I + Na[Mn(CO) 5 ] [9] Arrange BF 3, BCl 3 and BBr 3 in the increasing order of Lewis acidity and justify. Considering CO as an ideal gas, equipartition theorem predicts its total energy as 6.5 kt. S for a process is the same whether the process takes place reversibly or irreversibly. The quantity G equals the maximum non-expansion work done by a system in a constant temperature-pressure process. At constant temperature and pressure, G = 0 for a reversible phase change. Transition states cannot be isolated as independent chemical species. 4. The rate constank k for a second order reaction P + Q Products is expressed as 3000 log 10 k = 0, where the concentration is in mol lit 1, T is in absolute temperature T and time is in minutes. The initial concentrations of both the reactants are 0.05 M. Calculate the activation energy and half life of the reaction at 7 0 C. (R = cal K 1 mol 1 ). [15] [15] [6]

10 The equilibrium constant for the reaction 005 CH 10 Fe 3 O 4 (s) + CO(g) 3FeO(s) + CO (g) at C is If a mixture initially consisting of 1 mole of Fe 3 O 4, moles of CO, 0.5 mole of FeO and 0.3 mole of CO is heated to C at constant total pressure of 5 atmospheres, how many moles of each substance would be present at equilibrium? 44. Use the time-independent Schodinger equation to calculate the energy of a [15] particle of Mass m with V = 0 in the state 8 x y z sin sin sin in a 3 a a a a cubical box of length a. [9] At 0 0 C, the vapor pressure of two pure liquids X and Y which form an ideal solution are 70 torr and 0 torr respectively. If the mole fraction of X in solution is 0.5, find the mole fractions of X and Y in the vapor phase in equilibrium with the solution. [6]