PYQ DEC 2017 - VedPrep

CSIR NET CHEMISTRY (DEC-2017)
Previous Year Question Paper with Solution.

21. Among the following nuclear reactions of thermal neutrons, the cross section is highest for

(a)

(b)

(c)

(d)

Ans. d

Sol. The cross – section can be interpreted as the effective 'target area' that a nucleus interacts with an incident neutron. Larger the effective area, greater the probability for reaction.

In reaction, one neutron react with to give two neutron, which have more tendency to react with other radioactive nuclei. Thus, increases effective area for reaction.

Correct option is (d)

22. Spectrophotometric monitoring is not suitable to determine the end point of titration of

(a) oxalic acid vs potassium permanganate

(b) iron(II) vs 1, 10–phenanathroline

(d) nickel (II) vs dimethylglyoxime

Ans. a

Sol. Oxalic acid versus potassium permaganante:

End – point is colorless pink – purple

(b) Iron (II) versus 1, 10 – phenanthroline:

End – point is colorless Reddish – orange

(d) Nickel (II) versus Dimethylglyoxime:

End – point is colorless Red

End – point is Blue – green Blue

Since, color change at end – point is not significant for option (c) which is requirement of the spectrophotometric titration. Therefore, color mointoring method is not suitable in this case.

Correct option is (c)

23. The first ionization energy is the lowest for

(a) Br

(b) Se

(d) As

Ans. b

Sol. Generally, ionisation energy increases on moving from left to right in a period in periodic table.

Ionisation energy decreases as we move down in given group.

Ionisation energy will be more for full filled and half filled orbital.

Correct option is (b)

24. Among special with pyramidal shape is/are?

(a)

(b)

(c)

(d)

Ans. a

Sol.

Correct option is (a)

25. The role of BF₃ as an industrial plymerization catalyst is to generate

(a) carbanion

(b) carbocation

(d) cation radical

Ans. b

Sol.

Correct option is (b)

26. For the following complexes, the increasing order of magnetic moment (spin only value) is

(a) D < A < B < C

(b) C < A < D < B

(c)

(d)

Ans. a

Sol.

Hence, A < B < C = D

Correct option is (d)

27. The correct statement for cytochrome c is

(a) It is a non – heme protein

(b) The coordination number of iron in cytochrome c is five

(d) It can store or carry dioxygen

Ans. c

Sol. Cytochrome–C shows redox reaction and it is an essential component of electron transport chain, whereas it is carriers of one electron and does not bind oxygen

Correct option is (c)

28. Geometries of SNF₃ and XeF₂O₂, respectively, are

(a) square planar and square planar

(b) tetrahedral and tetrahedral

(d) tetrahedral and trigonal bipyramidal

Ans. d

Sol.

Correct option is (d)

29. The IR spectrum of Co(CO)₄H shows bands at 2121, 2062, 2043 and 1934 cm^–1. The V_Co-D (in cm^–1) expected in the spectrum of Co(CO)₄D is

(a) 2111

(b) 1396

(d) 1910

Ans. b

Sol.

Correct option is (b)

30. In trigonal prismatic ligand field, the most stabilized d orbital is

(a)

(b)

(c)

(d)

Ans. b

Sol. In trigonal prismatic ligand field, energy of 'd' orbital is

Hence, the most stablized 'd' orbital is d_xy

Correct option is (b)

31. The most unstable complex on the basis of electro–neutrality principle among the following is

(a)

(b)

(c)

(d)

Ans. b

Sol. According to electroneutrality principle, each atom in any stable substance has a charge close to zero. This means if central atom has more positive charge then it would be stabilized by ligand having high negative charge density i.e. more electronegative donor atom.

In case of , nitrogen is sp³ hybridized hence it is least electronegative hence least stable complex.

Correct option is (b)

32. The band in the electronic spectrum of 1₂ appearing at 520 nm will undergo maximum blue shift in

(a) water

(b) hexane

(d) methanol

Ans. d

Sol. Electronic absorption band of I₂ vapours appears at 520 nm i.e.

It solution is prepared with a solvent that able to form a charge transfer complex (CTC) like aromatic solvents, ethers, alcohols etc. This absorption band shifted towards UV range i.e. blue shift. More the donation of electrons from solvent to the of more will be the blue shift.

Here, option(d) methanol has highest electrons donating capacity (i.e. most basic)

Note: Methanol has low ionization potential (10.85 eV) than water (12.59 eV), therefore methanol is better electron donar than water.

Correct option is (d)

33. Mismatch among the following is

(a) Sharp transition and fluorescene in lanthanides

(b) Broad bands and d – d transitions

(d) Charge transfer and molar absorptivity of the order of 10⁴ L mol^–1 cm^–1

Ans. c

Sol. Spin – orbit coupling is larger for the heavier atoms (Inner transition) and very small for lighter atoms.

Correct option is (c)

34. Among the following, the compound that gives base peak at m/z 72 in the El mass spectrum is

(a)

(b)

(c)

(d)

Ans. a

Sol.

Correct option is (a)

35. The among molecule has

(a) plane of symmetry

(b) R configuration

(d) centre of symmetry

Ans. b

Sol.

Correct option is (b)

36. The following natural product Entcrodiol is a

(a) terpene

(b) steroid

(d) alkaloid

Ans. c

Sol.

Enterodiol is a lignan, formed by the action of intestinal bacteria on lignan precursors found in plants.

Correct option is (c)

37. The correct order of basicity for the following heterocycles is

(a) A > C > B

(b) C > A > B

(d) B > A > C

Ans. c

Sol.

Lesser is the availability of lone pair for donation, lesser is the basic behaviour.

Correct option is (c)

38. The kinetic product formed in the following reaction is

(a)

(b)

(c)

(d)

Ans. d

Sol.

Correct option is (d)

39. Among the structure given below, the one that corresponds to the most stable conformation of compound A is

(a)

(b)

(c)

(d)

Ans. a

Sol. Hydrogen bonding and no 1, 3 – diaxial interaction

Correct option is (a)

40. According to Frontier Molecular Orbital (FMO) Theory, the Highest Occupied Molecular Orbital (HOMO) of hexatriene in the following reaction is

(a)

(b)

(c)

(d)

Ans. d

Sol. HOMO of hexatriene in hv condition is molecular orbital has three nodes.

No. of nodes.

Correct option is (d)

41. The number of signals observed in the proton decoupled ¹³C NMR spectrum of the following compound is

(a) Five

(b) Six

(d) Thirteen

Ans. a

Sol.

42. The correct order of stability of the following carbocations is

(a) A > C > B

(b) B > C > A

(d) C > B > A

Ans. d

Sol.

Order of stability of carbocation C > B > A

Correct option is (d)

43. An optically pure organic compound has specific rotation of +40⁰. The optical purity of the sample that exhibits specific rotation of +32⁰ is

(a) 8%

(b) 12%

(d) 80%

Ans. d

Sol.

Correct option is (d)

44. The major product formed in the following reaction is

(a)

(b)

(c)

(d)

Ans. c

Sol.

Correct option is (c)

45. Correct match of the compounds in Column P with the IR stretching frequencies (cm^–1) in Column Q is

(a) I–B; II–C; III–A

(b) I–C; II–A; III–B

(d) I–A; II–C; III–B

Ans. c

Sol.

Correct option is (c)

46. The organic compound that displays following data is

(a)

(b)

(c)

(d)

Ans. a

Sol.

Correct option is (a)

47. The molecule with a C₂ axis of symmetry among the following is

(a) BH₂Cl

(b) CH₃Cl

(d) HOCl

Ans. a

Sol.

Once C₂ passing through 'B' and 'Cl' atoms, two hydrogen interchange their position but remain same molecule.

Correct option is (a)

48. The molecule that will show Raman spectrum, but not IR spectrum, among the following is

(a) H₂

(b) HCl

(d) CS₂

Ans. a

Sol. H₂ a homo diatomic molecule will have not change in dipole moment. Thus, it will be IR inactive but since H₂ having polarisability in a Raman spectra. Thus, it will be Raman active.

Correct option is (a)

49. Boron in CBl₃ has

(a) sp hybridization

(b) sp₂ hybridization

(d) no hybridization

Ans. b

Sol.

Correct option is (b)

50. The number of degencrate spatial orbitals of a hydrogen-like atom with principal quantum number n = 6 is

(a) 1

(b) 6

(d) 36

Ans. d

Sol. Orbital degencracy = n² = 6² = 36

Correct option is (d)

51. If then which of the following necessarily holds:

(a)

(b)

(c)

(d)

Ans. b

Sol.

Correct option is (b)

52. The correct statement among the following is ( is a hermitian operator)

(a)

(b)

(c)

(d)

Ans. b

Sol. which is a Hermitian operator and be operand

Therefore, eign value is positive.

Correct option is (b)

53. If the atoms/ions in the crystal are taken to be hard spheres touching each other in the until cell, then the fraction of volume occupied in the body centered cubic structure is

(a)

(b)

(c)

(d)

Ans. d

Sol. Packing fraction

Correct option is (d)

54. Repeated measurements of Pb in a lake water sample gave 3.2, t.2 and 7.2 ppb of Pb. Standard deviation in the measurement of Pb is

(a) 2 ppb

(b) 4ppb

(d)

Ans. a

Sol.

Correct option is (a)

55. The stability of lyophobic colloids is a consequence of the

(a) electrical double layer at the surface of the particles.

(b) van der Walls force between the particles

(d) shape of the particles

Ans. a

Sol. The stability of lyophobic colloids is a consequence of electrical double layer at the surface of the particles

Correct option is (a)

56. The equivalent conductance at infinite dilution of a strong electrolyte can be obtained from the plot of

(a)

(b)

(c)

(d)

Ans. b

Sol. For strong electrolyte, can be obtained from the plot of

Correct option is (b)

57. The number – average molar mass for a monodisperse polymer is related to the weight – average molar mass by the relation

(a)

(b)

(c)

(d)

Ans. d

Sol.

Correct option is (d)

58. For a sequence of consecutive reaction, the concentration of I would be, by steady state approximation.

(a)

(b)

(c)

(d)

Ans. d

Sol. Rate of formation of I = Rate of deformation of I

Correct option is (d)

59. Enthalpy is equal to

(a)

(b)

(c)

(d)

Ans. b

Sol.

Correct option is (b)

60. The structure of ribonucleoside uridine is

(a)

(b)

(c)

(d)

Ans. b

Sol.

Uridine is glycosylated pyrimidine – along containing uracil attached to ribose ring (ribofuranose) via a – N₁ – glycosidic bond

Correct option is (b)

61. The peak area of differential thermal analysis curve is proportional to one or more of the following:

A. mass loss

B. mass of the sample

C. heat of decomposition/phase change

The correct answer is

(a) A only

(b) B only

(d) B and C

Ans. d

Sol. The peak area of differential thermal analysis is propportional to

(i) mass of the sample

(ii) heat of decompositional phase change

Correct option is (d)

62. To determine the bond parameters at 25⁰C, electron diffraction is generally unsuitable for both

(a) O₃ and NO₂

(b) Sulfur and dry ice

(d) O₃ and dry ice

Ans. b

Sol. Electron differaction is used to get the bond parameters of gaseous samples.

Correct option is (b)

63. Match lanthanides in Colum I and with their properties in Column II

(a) A – (iii), B – (ii); C – (i); D – (iv)

(b) A – (ii), B – (iii); C – (iv); D – (i)

(d) A – (iii), B – (ii); C – (iv); D – (i)

Ans. a

Sol. (a) Lu (III) = [Xe] 4f¹⁴5d⁰6s⁰, hence diamagnetic

(b) EuI₂ has metallic lustre

(d) Tb(III)–f⁸ has pink colour

Correct option is (a)

64. Among the following species isolobal to CH₂ are

A. CpCr(CO)₂

B. CpCu

C. Ni(CO)₂

D. Cr(CO)₄

E. Fe(CO)₄

(a) A, C and E

(b) B, C and D

(d) A, B and D

Ans. c

Sol. Number of valence electron in CH₂ = 6

Hence, fragment having 16 electron will be isolobal to this fragment.

Correct option is (c)

65. Choose the incorrect statement for the phosphomolybdate anion,

(a) It has a Keggin structure

(b) Phosphorus is in +5 oxidation state

(d) It forms crystalline precipitates with [R₄N]⁺ (R = bulky alkyl or aryl group)

Ans. c

Sol. is less basic. It is slightly less basic than

Correct option is (c)

66. Consider the following statement(s) for actinides (An):

A. Oxidation states greater than +3 are more frequent in An compared to lathanides (Ln)

B. Some An (III) ions show d–d transitions

C. are stable

D. Some of actinides do not have radioactive isotopes

The correct answer is

(a) A and C

(b) B and C

(d) B, C and D

Ans. a

Sol. (A) Due to more expansion of 5f orbital actinoids has more tendency to release electron hence have more tendency to show oxidation state greater than +3 compared to Lanthanoids

(B) Actinoids (III) show either f – d or f – f transition, but no d – d transition

(D) All the actinoids have radioactive isotopes

Correct option is (a)

67. According to Bent's rule, for p – block elements, the correct combination of geometry around the central atom and position of more electro– negative substituent is

(a) Trigonal bipyramidal and axial

(b) Triogonal bipyramidal and equatorial

(d) Square pyramidal and basal

Ans. a

Sol. According to Bent's Rule, 'more electro negative element occupy axial position in trigonal bipyramidal geometry.

Correct option is (a)

68. Allred – Rochow electronegativity of an element is

A. directly proportional to the effective nuclear charge

B. directly proportional to the covalent radius

C. inversely proportional to the square of the covalent radius

D. directly proportional to the square of the effective nuclear charge

The correct answer is

(a) A and B

(b) A and C

(d) A and D

Ans. b

Sol. According to Allred – Rochow, electronegativity can be given as

where, r = covalent radius.

Correct option is (b)

69. Br₂ with propanonc forms a charge transfer complex and l₂ forms triiodidc anion with I^–. This implies that

(a) both Br₂ and I₂ act as bases

(b) both Br₂ and I₂ act as acids

(d) Br₂ acts as a base and I₂ acts an acid

Ans. b

Sol. In there is intraction between of and non – bonding electron of I^–. In case propanone and Br₂, there in interaction between of Br₂ and non – bonding electron of propanone.

Thus, both I₂ and Br₂ behave as acid.

Correct option is (b)

70. In the complex [Pd (L-L) (Me) (Ph], the bisphosphine (L-L) that does not allow reductive elimination of PhMe, is

(a)

(b)

(c)

(d)

Ans. d

Sol. According to reductive elimination reaction mechanism cis – complex can give the product but trans – complex is not suitable for reaction and does not give reductive elimination product. Since, ligand given in option (d) forms a trans – complex with Pd(II) due to the presence of flexible methylene (–CH₂–) groups. Therefore, reductive elimination not occured.

Correct option is (d)

71. In the reaction given below, the bisphosphine (P–P) that is in effective for transfer hydrogenation reaction is

(a) Diphenylphosphinomethane

(b) 1, 2–Diphenylphosphinoethane

(d) 1, 4–Diphyenylphosphinobutane

Ans. d

Sol. As the chelate ring size increases (in case of (d)), the energy of LUMO of complex cation CpRu(P–P)⁺ (which formed after H^– transfer) decreases and makes the complex cation better H^– acceptor and therefore decreasing the rate of H^– transfer from CpRu(P–P)H.

Correct option is (d)

72. For high spin and low spin d⁶ octahedral complexes (ML₆), the generally observed spin allowed transitions, respectively, are

(a) two and one

(b) one and two

(d) two and two

Ans. b

Sol. For d⁶ (high spin) there is one spin allowed transition from

In case of d⁶ low spin commonly two spin allowed transitions are observed.

there are additional spin allowed transitions at higher energy but they are marked by allowed transitions. Hence, are not observed.

Correct options is (b)

73. The reactions given below,

are examples of

(a) disproportionation only

(b) disproportionation (A) and solvation (B)

(d) solvalysis as well as disproportionation

Ans. d

Sol.

Above both reactions are example of solvolysis as well as disproportionation

Correct option is (d)

74. According to Wade's rules, the culster type and geometry of [Sn₉]⁴⁺, respectively, are

(a) closo and tricapped trigonal prismatic

(b) nido and monocapped square-antiprismatic

(d) closo and monocapped square antiprismatic

Ans. b

Sol. thus it follow 4n + 4. Hence, it has nido structure

Correct option is (b)*

75. Assuming the expected ³¹P NMR spectrum of

(a)

(b)

(c)

(d)

Ans. c

Sol.

Intensity ratio: 1 : 1 : 1 : 1 : 3 : 3 : 3 : 3 : 3 : 3 : 3 : 3 : 1 : 1 : 1 : 1

Correct option is (c)

76. The geometry around Cu and its spin state for K₃CuF₆ and KCuL₂, [H₂L=H₂NCONHCONH₂], respectively are:

(a) (octahedral, high-spin) and (square planar, low-spin)

(b) (octahedral, low-spin) and (square planar, low-spin)

(d) (trigonal prismatic, low-spin) and (tetrahedral, high-spin)

Ans. a

Sol.

Correct option is (a)

77. The active site structure for oxy-hemerythrin is:

(a)

(b)

(c)

(d)

Ans. c

Sol. In oxyhemerythrin, both the Fe are present as Fe(III) and there is presence of hydrogen bonding and dioxygen bind to only one Fe.

Correct option is (c)

78. Consider the following statements with respect to the base hydrolysis of [CoCl(NH₃)₅]²⁺ to [Co(NH₃)₅(OH)]²⁺.

A. One of the ammonia ligands acts as a Bronsted acid.

B. The entering group is water.

C. A hepatcoordinated Co³⁺ species is an intermediate.

The correct statement(s) is/are

(a) A and B

(b) A and C

(d) C only

Ans. a

Sol. Mechanism of base hydrolysis can be given as

Correct option is (a)

79. The number of inorganic sulfides in cubane like ferredoxin and their removal method, respectively. are

(a) eight and washing with an acid

(b) four and washing with a base

(d) four and washing with an acid

Ans. d

Sol. Cubane like ferredoxin is Fe₄S₄

It has four inorganic sulfide which can be removed by treatment with acid.

Correct option is (d)

80. Considering the ambidentate behaviour of thiocyanate ion, the most stable structure among the following is

(a)

(b)

(c)

(d)

Ans. a

Sol.

Correct option is (a)

81. Major product of the following reaction is

(a)

(b)

(c)

(d)

Ans. c

Sol.

Correct option is (c)

82. Major product in the following reaction is

(a)

(b)

(c)

(d)

Ans. a

Sol.

Correct option is (a)

83. Major product A and B of the following reaction sequence are

(a)

(b)

(c)

(d)

Ans. c

Sol.

Correct option is (c)

84. The major product formed in the following reaction is

(a)

(b)

(c)

(d)

Ans. c

Sol.

Correct option is (c)

85. Major products A and B of the following reaction sequence are

(a)

(b)

(c)

(d)

Ans. b

Sol.

Correct option is (b)

86. The major product formed in the following reaction is

(a)

(b)

(c)

(d)

Ans. d

Sol.

Correct option is (d)

87. Correct sequence of reagents (i) – (iii) required for the conversion of A to B is

A. Thionyl chloride, B. 4–Chloropyridine C. Piperidine

(a) A, B and C

(b) A, C and B

(d) C, A and B

Ans. c

Sol.

Correct option is (c)

88. The following reaction involves

(a) [1, 2] sigmatropic rearrangement

(b) [2, 3] sigmatropic rearrangement

(d) C – H insertion reaction

Ans. b

Sol.

Correct option is (b)

89. Correct sequence of steps involved in the following transformation is

(a) Michael addition, aldol condensation, syn-elimination, keto-enol tautomerism

(b) aldol condensation, electrocyclic ring closing, syn-elimination, dehydrogenation

(d) Robinson annulation, dehydrogenation, anti-elimination

Ans. a

Sol.

Correct option is (a)

90. The major products A and B in the following reaction sequence are

(a)

(b)

(c)

(d)

Ans. a

Sol.

Correct option is (a)

91. The major product formed in the following reaction sequence is

(a)

(b)

(c)

(d)

Ans. b

Sol.

Correct option is (b)

92. The number of optically active steroisomers possible for

(a) Two

(b) Four

(d) Eight

Ans. a

Sol. The Number of optically active stereoisomer are two

Correct option is (a)

93. The correct match of the circled protons in Column P with ¹H NMR chemical shift ( δ ppm ): Column Q is

(a) I–A; II–B; III–C

(b) I–B; II–A; III–C

(d) I–C; II–B, III–A

Ans. b

Sol.

Correct option is (b)

94. The major product formed in the following reaction sequence is

(a)

(b)

(c)

(d)

Ans. b

Sol.

Correct option is (b)

95. For the successful synthesis of peptide linkage leading to the product A, the side chain of the amino acid B should have

(a) XH = –OH

(b) XH = –(CH₂)₄NH

(d) XH = – SH

Ans. d

Sol.

Correct option is (d)

96. The major products A and B in the following reaction sequence are

(a)

(b)

(c)

(d)

Ans. a

Sol.

Correct option is (a)

97. The intermediate A and the major product B in the following reaction are

(a)

(b)

(c)

(d)

Ans. a

Sol.

Correct option is (a)

98. The correct intermediate which leads to the product in the following reaction in

(a)

(b)

(c)

(d)

Ans. c

Sol.

Correct option is (c)

99. In the following transformation, the mode of electrocyclization A and the major product B are

(a)

(b)

(c)

(d)

Ans. b

Sol.

Correct option is (b)

100. The major product A and B in the following reaction sequence are

(a)

(b)

(c)

(d)

Ans. b

Sol.

Correct option is (b)

101. The correct statement about the symmetry of the eigenfunctions of a quantum of 1–D harmonic oscillator is

(a) All the eigenfunctions are only even functions, because the potential is an even function.

(b) All the eigenfunctions are only odd functions, although the potential is an even function.

(d) All the eigenfunctions are either odd or even functions, because the potential is an even function.

Ans. d

Sol. Eigen functions are even for even values of vibrational quantum number (n) and odd for odd values of n.

Correct option is (d)

102. The correct statement about the difference of second and first excited state energies of a particle in 1–D, 2–D square and 3–D cubic boxes with same length for each, is

(a)

(b)

(c)

(d)

Ans. c

Sol.

Correct option is (c)

103. A one – dimensional quantum harmonic oscillator is perturbed by a potential The first order correction to the energy for the ground state (DE⁽¹⁾) is

(a)

(b)

(c)

(d)

Ans. c

Sol. For odd power of perturbed potential, is always '0'

Correct option is (c)

104. The normal mode of ethylene represented, by the figure below, is

(a) only IR active

(b) only Raman active

(d) neither IR nor Raman active

Ans. b

Sol. Only Raman active, (symmetric vibration, change in dipole moment is zero during vibration)

Correct option is (b)

105. The pair that contains a spherical top and a symmetric top, among the following, is

(a)

(b)

(c)

(d)

Ans. c

Sol.

Correct option is (c)

106. A part of the character table of a point group (of order 4) is given below.

The four characters of are, respectively

(a) 1, 1, –1, –1

(b) 2, 0, 0, 1

(d) 1, –i, i, –1

Ans. a

Sol. According to GOT theorem, any two IR must be orthogonal to each other.

Correct option is (a)

107. The electronic transition energy from in propenyl radical is 4.8 eV. Within the frame work of Huckel theory, the transitions energy from would be

(a) 2.4 cV

(b) 4.8 cV

(d) 14.4 cV

Ans. c

Sol.

Correct option is (c)

108. The g – factors of ¹H and ¹³C are 5.6 and 1.4 respectively. For the same value of the magnetic field strength, if the ¹H resonates at 600 MHz, the ¹³C would reasonate at

(a) 2400 MHz

(b) 600 MHz

(d) 38 MHz

Ans. c

Sol.

Correct option is (c)

109. The term symbol for the ground state of a metal ions is ³P₂. The residual entropy of a crystal of a salt of this metal ion at 0 K is

(a)

(b)

(c)

(d)

Ans. c

Sol.

Correct option is (c)

110. In stretching of a rubber band.

Which of the following relations in true?

(a)

(b)

(c)

(d)

Ans. a

Sol.

Similarly differentiating equation (1), w.r.t. L at constant P and T

Correct option is (a)

111. For distinguishable molecules are distributed in energy levels E₁ and E₂ with degeneracy of 2 and 3, respectively. Number of microstates, with 3 molecules in energy level E₁ and one in energy level E₂, is

(a) 4

(b) 12

(d) 192

Ans. c

Sol. For distinguishable particles,

Correct option is (c)

112. One mole of an ideal gas undergoes a cyclic process (ABCDA) starting from point A through 4 reversible steps as shown in the figure. Total work done in the process is

(a)

(b)

(c)

(d)

Ans. d

Sol.

Correct option is (d)

113. If the specific conductance of an electrolyte solution is and cell constant is 0.25 cm^–1, the conductance of the solution is

(a)

(b)

(c)

(d)

Ans. c

Sol.

Correct option is (c)

114. The predicted electromotive force (emf) of the electrochemical cell

(a) –0.850 V

(b) +0.044 V

(d) –0.044 V

Ans. b

Sol.

Correct option is (b)

115. A polymer has the following molar mass distribution

The calculated number average molar mass of the polymer is

(a) 5200

(b) 5600

(d) 6000

Ans. b

Sol.

Correct option is (b)

116. The separaton of the (123) planes of an orthorhombic unit cell is 3.12 nm. The separation of (246) and (369) planes are, respectively,

(a) 1.56 nm and 1.04 nm

(b) 1.04 nm and 1.56 nm

(d) 1.04 nm and 3.12 nm

Ans. a

Sol.

Correct option is (a)

117. The slope and intercept obtained from (1/Rate) against (1/substrate concentration) of an enzyme catalyzed reaction are 300 and 2×10⁵, respectively. The Michaelis–Menten constants of the enzyme in this reaction is

(a) 5 × 10⁶ M

(b) 5 × M^–6 M

(d) 1.5 × 10^–3M

Ans. d

Sol.

Correct option is (d)

118. The pressure inside (P_in)a sperical cavity with a radius r formed in a liquid with surface tension is related to the external pressure (P_out) as

(a)

(b)

(c)

(d)

Ans. b

Sol. For a bubble, surface tension counteracts internal pressure

Correct option is (b)

119. Reaction between A and B is carried out for different initial concentrations and the corresponding half-life times are measured. The data listed in the table: