QUESTION PAPER CHEMISTRY-CY

Transcription

1 Q.1 Q.5 : Carry E mark each. CEMISTRY-CY 1. Jahn-Teller distortion of CuS 4.5 acts to Raise symmetry Remove an electronic degeneracy Cause loss of ligand Promote a d-electron to an antibonding molecular orbital.. Among the following, the group of molecules that undergoes rapid hydrolysis is: SF 6, Al Cl 6, Si 4 BCl 3, SF 6, SiCl 4 BCl 3, SiCl 4, PCl 5 SF 6, Al Cl 6, SiCl 4 3. The reaction of solid XeF with AsF 5 in 1:1 ratio affords XeF 4 and AsF 3 XeF 6 and AsF 3 [XeF] + [AsF 6 ] [Xe F 3 ] + [AsF 6 ] 4. A well known naturally occuring organometallic compound is: vitamin B 1 coenzyme chlorophyll cytochrome P-450 myoglobin 5. The complex that exists as a pair of enantiomers is trans-[co( C C ) Cl ] + cis-[co( 3 ) 4 Cl ] + [Pt(PPh 3 )(Cl)(Br)(C 3 )] [Co( C C ) 3 ] The region of electromagnetic spectrum employed in the electron spin resonance (ESR) spectroscopy is: radiowave microwave infrared visible 7. The red color of oxyhaemoglobin is mainly due to the d-d transition metal to ligand charge transfer transition ligand to metal charge transfer transition 8. The band structure in an n-type semiconductor is intraligand * transition. 1 Energy I II III IV I II III IV 9. In the following reaction S The major product is: Ac /aac eat S Ac S CC 3 S

2 10. In the following reaction sequence (i).cl (ii) ArS Cl, Py (iii) eat (iv) the major product is: 11. The diene which undergoes Diels-Alder reaction with maleic anhydride is: 1. The sequence of an mra molecule produced from a DA template strand with the composition 5' AGCTACACT 3' is 5' AGUGUAGCU 3' 5' UCGAUGUGA 3' 5' AGTGTAGCT 3' 5' TCGATGTGA 3' 13. In the following reaction, the major product is: Et Et Et eat C

3 3 Et 14. The structure of the dipeptide Ala-Pro derived from the natural amino acids is: C C C 15. In the following reaction C the major product is: Ts (i) eq. n-buli -78ºC to 0ºC (ii) DMF C C C 16. In the following reaction, C + the major product is:

4 4 17. For a given first order reaction, the reactant reduces to 1/4 th its initial value in 10 minutes. The rate constant of the reaction is: min min mol L 1 min mol L 1 min The freezing point constant for water is 1.86 K (mol kg 1 ) 1. The change in freezing point when 0.01 mol glucose is added to 1 kg water is: 1.86 K 1.86 K K K 19. n the pressure-temperature diagram for a one-component system, the point where the solid-liquid and the liquid-gas curves intersect is: triple point critical point melting point boiling point 0. The wave function for a harmonic oscillator described by x exp x / ne maximum only Two maxima, one minimum only has ne maximum, one minimum only Two maxima, two minima only 1. If an arbitrary wave function is used to calculate the energy of a quantum mechanical system, the value calculated is never less than the true energy. The above statement relates to Perturbation theory Variation principle eisenberg s uncertainty principle quantization of energy. The point group symmetry of the given planar shape is: D 3h C 3 C 3h C 3v 3. G P T V S S V 4. Volume Temperature According to Ehrenfest classification of phase transitions, the above diagram refers to Zeroth order phase transition First order phase transition Second order phase transition transition.

5 5. According to conventional transition state theory, for elementary bimolecular reactions, the molar entropy of activation 0 S is : Positive Zero egative Positive for endothermic and negative for exothermic reactions. Q.6 Q.55 : Carry TW marks each. 6. The crystal field stabilization energy (CFSE) value for [Ti( ) 6 ] 3+ that has an absorption maximum at 49 nm is: 0, 35 cm 1 1, 195 cm 1 10, 16 cm 1 8, 130 cm 1 7. For Et AlX (X = PPh, Ph, Cl and ), the tendency towards dimeric structure follows the order PPh Cl Ph Cl PPh Ph Ph Cl PPh Ph PPh Cl 3 8. In the isoelectronic series, V, Cr and Mn, all members have intense charge transfer (CT) transitions. The ICRRECT statement is CT transitions are attributed to excitations of electrons from ligand to metal (e) Mn 4 exhibits charge transfer at shortest wavelength among the three 3 The wavelength of transitions increase in the order V Cr Mn The charge on metal nucleus increases in the order V Cr Mn The increasing order of wavelength of absorption for the complex ions (i) 3 (ii) CrCl 3 6 Cr 3 6 Cr 6 Cr C 6, is iv < ii < i < iii iv < iii < ii < i iv < i < iii < ii ii < iii < i < iv (iii) 3 (iv) 30. The total number of metal-metal bonds in Ru 3 (C) 1 and Co 4 (C) 1, respectively, is 3 and 6 4 and 5 zero and 4 3 and According to VSEPR theory the shapes of [SF Cl] + and [S 4 ] should be trigonal planar for [S 4 ] and trigonal pyramidal for [SF Cl] + both trigonal planar trigonal pyramidal for [S 4 ] and trigonal planar for [SF Cl] + both trigonal pyramidal 3. The product of the reaction between C 3 Mn(C) 5 and 13 C is: (C 13 3 C)Mn(C) 5 (C 3 C)Mn(C) 4 ( 13 C) ( 13 C 3 C)Mn(C) 5 C 3 Mn(C) The correct pair of 1 and 31 P MR spectral patterns for C()(F)(PCl ) is: 3 5

6 6 34. In the following reaction + Ph C ac(cat.) DMF the major product is: Ph Ph Ph Ph 35. In the following reaction, (i) Se /Ac (ii) a (iii) 3 + the major product is: C C C C 36. In the following reaction, Br Bu 3 Sn, AlB Toluene, heat

7 the major product is: The most appropriate sequence of reactions for carrying out the following conversion is (i) Peracid; (ii) + ; (iii) Zn/dil. Cl (i) Alkaline KMn 4 ; (ii) ai 4 ; (iii) 4 /K (i) Alkaline KMn 4 ; (ii) + ; (iii) Zn/dil. Cl (i) 3 / S; (ii) aet; (iii) 4 /K 38. In the following reaction sequence + (i) PTSA, C 6 6, heat (ii) CCl 3, a (iii) 3 + the major product is: Cl Cl Cl 39. In the following conversion (i) Cu (ii) I Li Si Bu t C, MPTA the major product is: C Si Bu t

8 8 C Si Bu t C Si Bu t C 40. In the following reaction, Si Bu t + S I (i) K t Bu (ii) Raney i, Et the major product is: S S 41. In the reaction, Ac.KAc ptically pure (+)-trans--acetoxycyclohexyl tosylate X the major product is: racemic trans-1, -cyclohexanediol diacetate optically active trans-1, -cyclohexanediol diacetate racemic cis-1, -cyclohexanediol diacetate optically active cis-1, -cyclohexanediol diacetate. 4. The activity of water at 11 bar and 98K is:

9 43. For the process 1 Ar 300K,1 bar 1 Ar 00K,10 bar assuming ideal gas behavior, the change in molar entropy is: 7.57 J K 1 mol J K 1 mol J K 1 mol J K 1 mol The wave function for a quantum mechanical particle in a 1-dimensional box of length a is given by x A sin a The value of A for a box of length 00 nm is (nm) 1 10 nm 1 /10 nm 0.1 (nm) 1/ 45. For 1 mole of a monoatomic ideal gas, the relation between pressure (p), volume (V) and average molecular kinetic energy is p A V p A 3V p A 3V p A 3V 46. For a 1 molal aqueous acl solution, the mean ionic activity coefficient and the Deby-uckel Limiting Law constant (A) are related as log A log A For the concentration cell M M + (aq, 0.01 mol dm 3 ) M + (aq, 0.1 mol dm 3 ) M the EMF (E) of the cell at a temperature (T) equals RT.303 F A RT.303 F 10 A 9 E RT.303 F 0 M /M E 0 M /M RT.303 F Commond Data Questions: Commond data for Q.48 and Q.49: A hypothetical molecule XY has the following properties Reduced mass: 10 6 kg X Y bond length: 100 pm Force constant of the bond: 8 10.m The frequency of radiation (in cm 1 units) required to vibrationally excite the molecule from v = 0 to v = 1 state is The frequency of radiation (in cm 1 units) required to rotationally excite the molecule from J = 0 to J = 1 state is Common data for Q.50 and Q.51: a P 4 and a P 4 on heating at high temperature produce a chain sodium pentaphosphate quantitatively. 50. The ideal molar ratio of a P 4 to a P 4 is: 4 : 1 1 : 4 3 : : The total charge on pentaphosphate anion is:

10 Linked Answer Q.5 and Q.53: The decomposition of ozone to oxygen g 3 g k (i) 1 occurs by mechanism 3 M g g g g M g, E 3 a,1 k (ii) g g M g M g g, E 3 a, k (iii) 3 g g g, E 3 a,3 where, M is the catalyst molecule. k i ' are rate constants and k a,i 's the activation energies for the elementary steps, d 5. Under the steady state approximation for the intermediates, the rate of decomposition of ozone, dt k1k3 3 M k M k 3 3 kk3 3M k M k Assuming k k M E E a,1 a,3 E a, 3 3 k1k3 3 M k M k 3 3 k1k 3 M k M k 3 3, the activation of the overall reaction is Ea,3 Ea,1 Ea, E a, E a,1 Statement for Linked Answer Q.54 and Q.55: A ketone on treatment with bromine in methanol gives the corresponding monobromo compound having molecular formula C 5 9 Br. The compound when treated with a in produces [Y ] as the major product. The spectral data for compound [X ] are: 1 MR: 1.17(d, 6), 3.0 (m, 1), 4.10(s, ); 13 C MR: 17, 37, 39, The compound is: 10 3, is Br Br Br Br 55. The major product [Y] is: ***** ED F TE *****