(c) S. orbital is (a) 1 (b) 0 (c) +1 (d) undefined.

Transcription

1 QUESTI PAPER CEMISTRY-CY Q. Q.25 : Carry E mark each.. The maximum non-pv work that a system can perform at constant P is 2. Consider the reaction : G S A A B C The unit of the thermodynamic equilibrium constant for the reaction is mol L L mol mol 2 L 2 dimensionless 3. The number of IR active vibrational normal modes of C 2 is 4. The number of C 2 axes in CCl 4 is 5. The value of the magnetic quantum number of a p x orbital is 0 + undefined. 6. The molecular partition function for a system in which the energy levels are equispaced by, is e e e e 7. A monoatomic gas, X, adsobred on a surface, Langmuir adsorption isotherm. A plot of the fraction of surface coverage, against the concentration of the gas [X], for very low concentration of the gas, is described by the equation K X K X /2 K X /2 K X K X 8. At a given temperature and pressure, the ratio of the average speed of hydrogen gas to that of helium gas is approximately 9. An example of nido-borane from the following is B 4 0 B 6 0 B 6 2 B The geometries of i(c) 4 and [icl 4 ] 2, respectively, are tetrahedral and square planar square planar and tetrahedral tetrahedral and tetrahedral square planar and square planar. The number of S S bonds in 2 S 5 6 is 2. In atomic absorption spectroscopy, the atomization process utilizes flame electric field magnetic field electron beam 3. At room temperature, the number of singlet resonances observed in the MR spectrum of 3 CC() 2 ( dimethyl pivalamide) is 4. Amongst the following, the metal that does T form homoleptic polynuclear carbonyl is Mn Fe Cr Co 5. The reaction of [Cp 2 Ta 2 ]I (Cp = C 5 5 ) with a yields. [Cp 2 Ta() 2 ]I [Cp 2 Ta()]I Cp 2 Ta() = C 2 Cp 2 Ta() = C 2 6. The complexes [Co( 2 ) 4 Cl 2 ] 2 and [Co( 2 ) 4 Cl( 2 )]Cl are linkage isomers positional isomers ionization isomers optical isomers

2 QUESTI PAPER 7. The major product of the following reaction is 2. 2 S 4, a 2. Cl, 2 8. Amongst the following, the structure of guanosine is The correct order of IR stretching frequency of the C C in the following olefins is (I) (II) (III) I > II > III II > III > I III > II > I III > I > II 20. The correct order of the solvolysis for the following chlorides in acetic acid is Cl Cl Cl (I) (II) (III) II > I > III III > II > I III > I > II I > III > II

3 QUESTI PAPER 2. Formation of the product in the following photochemical reaction involves hv di- -methane rearrangement Paterno-Buchi reaction [2, 3]-sigmatropic rearrangement orrish type I reaction 22. The correct order of stability for the following conformations of cyclohexane is 3 (I) (II) (III) I > II > III I > III > II II > I > III III > I > II 23. The major product formed in the following reaction is + C 2 TiCl4 C 2 C 2 C The overall yield (in %) for the following reaction sequence is C 2 C MgBr 90% Jone's reagent 80% C aq. a 80% 25. The most suitable reagent combination to effect the following conversion is Bz Bz Bn Bn (i) a, CS 2, then I; (ii) Bu 3 Sn, AlB, C 6 6, Reflux. (i) I 2, P 3, imidazole; (ii) 2, 0% Pd-C, Ac, high pressure (i) 3 SiCl, pyridine, DMAP; (ii) Bu 3 Sn, AlB, C 6 6, reflux (i) MsCl, pyridine, DMAP; (ii) LiAl 4, TF, reflux, Q.26 Q.55 : Carry TW marks each. 26. r Zr/3 6 Z r e cos, is a proposed hydrogenic wavefunction, where Z = atomic number, r = radial distance from the nucleus, = azimuthal angle, is a constant. The ICRRECT statement about is 0 in the xy-plane two radial nodes are presenet in one angular node is present in the size of the orbital decreases with increase in atomic number

4 QUESTI PAPER 27. The van der waals constant a and b of C 2 are 3.64 L 2 bar mol 2 and 0.04 L mol, respectively. The value of R is bar dm 3 mol K. If one mole of C 2 is confined to a volume of 0.5L at 300K, then the pressure (in bar) exerted by the gas, is 28. A plot of osmotic pressure against concentration (gl ) of a polymer is constructed. The slope of the plot increases with increase in temperature increases with increase in molar mass of the polymer decreases with decrease in concentration of the polymer decreases with increase in temperature. 29. A platinum electrode is immersed in a solution containing 0. M Fe 2+ and 0. M Fe 3+. Its potential is found to be 0.77V against SE. Under standard conditions and considering activity coefficients to be equal to unity, the potential of the electrode, when the concentration of Fe 3+ is increased to M, is 30. Molybdenum crystallizes in a bcc structure with unit cell dimensions of 0.34 nm. Considering the atomic mass of molybdenum to be 96, its density (in kg m 3 ) is 3. The ratio of molecules distributed between two states is at 300K. The difference in energy (in kj mol ) of the two states is 32. A Carnot engine operates at 55% efficiency. If the temperature of reject steam is 05ºC, then the absolute temperature of input steam is 33. f the following plots, the correct representation of chemical potential (µ) against absolute temperature (T) for a pure substance is (S, L and g denote solid, liquid and gas phases, respectively) µ S L T g µ S L T g 34. The enthalpy of fusion of ice at 273K is 6.0 kj mol and the enthalpy of vaporization of water at 273K is kj mol. The enthalpy of sublimation (in kj mol ) of ice at 273K, is 35. Suppose and 2, are two hybrid orbitals: and s 3 px 3 py The angle (in degrees) between them is µ S L T g µ S L s px py 36. BCl 3 and 4 Cl were heated at 40ºC to give compound X, which when treated with ab 4 gave another compound Y. Compounds X and Y are B Cl 3 and B B Cl 3 and B B Cl 3 and B B 3 3 Cl 6 and B The number of microstates in term G is 38. The set of protons (underlined) in C 3 C 2 C 2 C 3 that would exhibit different splitting patterns in high (500 Mz) and low (60 Mz) field MR, is C 3 C 2 C 2 C 3 C 3 C 2 C 2 C 3 C 3 C 2 C 2 C 3 C 3 C 2 C 2 C Amongst the following, the complex ion that would show strong Jahn-Teller distortion is [Cr( 2 ) 6 ] + [Ti( 2 ) 6 ] 3+ [Co( 2 ) 6 ] 2+ [Fe( 2 ) 6 ] Amonst the following, the metal carbonyl species having the highest C stretching freqency is [Mn(C) 6 ] + Cr(C) 6 [V(C) 6 ] [Fe(C) 4 ] 2 T g 4

5 QUESTI PAPER 5 4. The correct order of thermal stability for the given compounds is Ti 4 > Ti(C 2 C 3 ) 4 > TiEt 4 TiEt 4 > Ti(C 2 C 3 ) 4 > Ti 4 Ti 4 > TiEt 4 > Ti(C 2 C 3 ) 4 Ti(C 2 C 3 ) 4 > Ti 4 > TiEt Amongst the following, the complex ion that is expected to the highest magnetic moment at room temperature is [i(c) 4 ] 2 [Fe(C) 6 ] 3 [Cu( 2 ) 6 ] 2+ [Co(C) 6 ] MnCr 2 4 is normal spinel with total CFSE of 5.5 Dq inverse spinel with total CFSE of 5.5 Dq normal spinel with total CFSE of 24 Dq inverse spinel with total CFSE of 24 Dq 44. Mg 2+ is preferred in photosynthesis by chlorphyll because it has strong spin-orbit coupling it has weak spin-orbit coupling it is a heavy metal it binds strongly with chlorophyll 45. In Monsanto acetic acid process shown below, the role of I is Rh catalyst/i C C C C 3 80ºC, 30 bar 3 2 to convert C 3 to a stronger nucleophile (C 3 ) to reduce the Rh(I) catalyst to a Rh(0) species to reduce a Rh(III) active species to a Rh(I) species in the catalytic cycle to convert C 3 to C 3 I 46. Formation of the ketone from the diazoketone I involves 2 I CAg heat generation of carbene and a [2, 3]-sigmatropic rearrangement generation of carbene and an electrocyclic ring closing reaction generation of ketene and a [2+2] cycloaddition generation of ketene and a [3, 3]sigmatropic rearrangement 47. The major products X and Y formed in the following reaction sequence are II S + C 2 heat X Raney i 25ºC Y C 2 C 2 S

6 QUESTI PAPER 6 C 2 S S S C 2 S C 2 S C The major products X and Y formed in the following reactions are l 25ºC X a, l Y I I I 49. The major product X and Y formed in the following reaction sequence are h C62 I2 air cis stilbene X Y

7 QUESTI PAPER The product of the following reaction gave 6 line 3 C MR spectrum with peaks at 75, 52, 50, 46, 37, 33 ppm. The structure of the product is 2 hv 5. The major product formed in the following reaction is D Se 2 2 heat C The major products X and Y formed in the following reaction sequence are D D C 2 2 X TiCl 3 Eta, Et 2 Y

8 QUESTI PAPER The major products X and Y formed in the following reaction sequence are C 2 2 S 4 2 Cbz-Cl ( equiv.) X aq. ac 3 Y C 2 C 2 2 Cbz C 2 C 2 2 Cbz C 2 C 2 2 Cbz 2 C 2 C 2 Cbz

9 QUESTI PAPER 54. Given the fact that, 3-butadiene has a UV absorption of 27nm, the absorption wavelength (in nm) for the conjugated system shown below is 9 (Use these absorption values for auxochromic groups: alkyl : +5; exo-cyclic double bond : +5; every additional conjugated C = C : + 30) 55. The m/z value of the detectable fragment formed by McLafferty like rearrangement of the following compound in mass spectrometer is C ***** ED F TE QUESTI PAPER *****