UPSC Previous Year Question Paper-Combined Geo-Scientist (Preliminary) Examination-2026-CHEMISTRY
TEST BOOKLET Paper II CHEMISTRY
UPSC Previous year question paper Geo scientist exam
1. Radial distribution function does NOT depend upon (a) Distance from the nucleus (b) Principal quantum number (c) Azimuthal quantum number (d) Orientation of orbital
2. Which one of the following statements regarding wave functions is NOT correct? (a) Wave functions are three dimensional and contain three quantum numbers n, l and m (b) Wave functions represent total movement of a particle over a period (c) Probability density is interpreted as the square of wave function (d) Wave functions should be differentiable
3. Which of the following statements regarding electron configuration of atoms is/are correct? 1. Principal quantum number = 1, K shell, example : He 2. Principal quantum number = 3, M shell, example : Ne 3. Principal quantum number = 2, L shell, example : F 4. Principal quantum number = 3, K shell, example : Si Select the answer using the code given below : (a) 1 only (b) 1 and 3 only (c) 2 and 4 (d) 1, 2 and 3
4. Which one of the following represents the correct order of boiling point among Li, Be, B and Zn ? (a) B > Li > Be > Zn (b) Zn > Be > B > Li (c) Li > Be > Zn > B (d) B > Be > Li > Zn
5. The correct group, period and block for element Hassium (Hs) is (Given : atomic number of Hs = 108) (a) 13th group, 7th period, p-block (b) 15th group, 7th period, p block (c) 6th group, 6th period, d-block (d) 8th group, 7th period, d-block
6. Consider the following statements regarding the modern periodic table : 1. Elements in group 16 are also known as chalcogens 2. Elements in groups 3-12 are known as p-block elements 3. The f-block elements are also known as inner transition elements 4. Elements of groups 13-18 are known as transition elements 5. Elements in group 2 are also known as alkaline earth metals Which of the statements given above are correct ? (a) 2 and 4 (b) 1, 4 and 5 (c) 1, 3 and 5 (d) 3, 4 and 5
UPSC Previous year question paper Geo scientist exam
7. Which one of the following statements regarding general properties of s, p, d and f-block elements is NOT correct ? (a) The compounds of s and p-block elements are mostly white in color (b) All s-block elements are metals (c) Most stable oxidation state for all lanthanides is 3+ (d) The complexing ability of lanthanides is more in comparison with the d-block elements
8. Which of the following order(s) of ionic radii is/are correct ? 1. O2- < S2- < Se2- < Te2- 2. Ti2+ < Ti3+ < Ti4+ 3. O2- < F- < Na+ < Mg2+ Select the answer using the code given below : (a) 1 only (b) 1 and 2 only (c) 2 and 3 only (d) 1, 2 and 3
9. Which one of the following is the correct value of the effective nuclear charge (Zeff) for the 3d electron of chromium ? (a) 4.95 (b) 11.0 (c) 4.60 (d) 11.35
10. Which one of the following represents the correct order of solubility of Li2CO3, Na2CO3, K2CO3, Rb2CO3 and Cs2CO3 in water ? (a) Li2CO3 > Na2CO3 > K2CO3 > Rb2CO3 > Cs2CO3 (b) Cs2CO3 > Rb2CO3 > K2CO3 > Na2CO3 > Li2CO3 (c) Na2CO3 > Li2CO3 > K2CO3 > Rb2CO3 > Cs2CO3 (d) Cs2CO3 > Li2CO3 > Rb2CO3 > K2CO3 > Na2CO3
11. Which one of the following is expected to possess highest electronegativity ? (a) Al (b) Ga (c) In (d) Tl
12. Consider the following statements regarding catenation tendency of nitrogen : 1. Nitrogen has weaker catenation tendency than carbon due to repulsion between non-bonding lone pair electrons on nitrogen 2. Single bond energy of CH3-CH3 is much higher than H2N-NH2 3. Three or more nitrogen atoms can be joined through some multiple bonds Which of the statement(s) given above is/are correct ? (a) 1, 2 and 3 (b) 1 and 2 only (c) 1 only (d) 3 only
UPSC Previous year question paper Geo scientist exam
13. Which one of the following is expected to exist in gaseous state ? (a) WF6 (b) UF4 (c) TiCl4 (d) ScCl3
14. Which one of the following metal ions is diamagnetic ? (a) Ti3+ (b) V3+ (c) Cu+ (d) Co2+
15. Which one of the following is the most unstable in nature ? (a) PF5 (b) AsCl5 (c) SbCl5 (d) BiF5
16. The hydrolysis of SiCl4 proceeds through (a) SN1 mechanism (b) SN2 mechanism (c) Proton transfer (d) Reductive elimination
17. Which one of the following combination of products, respectively are formed during the reaction of diborane with oxygen and water ? (a) B2O3, B(OH)3 (b) B2O3, B2H5OH (c) B(OH)3, B2O2 (d) B2O2, B2H5OH
18. The radius of Na+ ion is 0-95 Å and that of Cl- ion is 1-81 Å. In which one of the following sites Na+ ions will prefer to occupy in the crystal lattice of Cl- ions ? (a) Plane trigonal (b) Tetrahedral (c) Octahedral (d) Body-centred cubic
19. Consider the following information available for an ionic binary compound : 1. Madelung Constant 2. Interionic distance 3. Charges of the anions and cations 4. Ionic radii of anions and cations Which of the information given above is/are required to estimate lattice energy using Born-Lande equation ? (a) 3 only (b) 1 and 2 only (c) 1, 2 and 3 only (d) 1, 2, 3 and 4
20. Which of the following statement(s) regarding polarizability is/are correct ? 1. Small, highly charged cations have high polarizing power 2. Large, highly charged anions are easily polarized 3. Cations that do not have a noblegas electron configuration are easily polarized Select the answer using the code given below : (a) 1,2 and 3 (b) 1 only (c) 3 only (d) 1 and 2 only
21. Sodium chloride reacts with sodium vapour to give a non-stoichiometric compound Na1+δCl. This leads to (a) Frenkel defect (b) Schottky defect (c) F center (d) Wadsley effect
22. The number of type of bonds between two carbon atoms in calcium carbide is (a) One σ and one π (b) One σ and two π (c) Two σ and one π (d) Two σ and two π
23. Which one of the following is a correct combination of coordination number, geometry and hybridization ? (a) 3, linear, sp3 (b) 5, trigonal pyramidal, sp3d2 (c) 4, square planar, sp2d (d) 3, tetrahedral, sp3
24. [Figure: Structure H-N=N-N] The correct order of bond lengths in the above structure is (a) II > I > III (b) I > II > III (c) III > II > I (d) II > III > I
25. The spin only magnetic moment of [Cr(CO)6] is (a) 2-84 BM (b) 5-92 BM (c) 4-90 BM (d) 0 BM (diamagnetic)
26. Which of the following statement(s) regarding hydrazine is/are correct ? 1. It acts as an ambidentate ligand 2. It acts as a monodentate ligand 3. It acts as a bridging ligand 4. It does not bind with metal Select the answer using the code given below : (a) 4 only (b) 2 only (c) 1 and 3 (d) 2 and 3
UPSC Previous year question paper Geo scientist exam
27. Which one of the following is the correct IUPAC name for the compound K2[Cr(CO)(NH3)(CN)4] ? (a) Potassium amminetetracyano- carbonylchrome(III) (b) Potassium amminecarbonyltetracyanochromate(II) (c) Potassium amminecarbonyltetracyanochromate(0) (d) Potassium amminetetracyano- carbonylchrome(I)
28. The meridional isomer of a coordination compound [MA3B3] contains: (where, M is the metal and A and B are ligands) (a) All A and B ligands arranged at the vertices of a planar hexagon (b) All A ligands in one plane and B ligands in a perpendicular plane in octahedral geometry (c) A and B ligands randomly arranged at the vertices of an octahedron (d) All A or B ligands are adjacent, occupying the vertices of a triangular face of octahedron
29. [Co(NH3)3Cl3] exhibits (a) Fac- and mer- geometrical isomerism (b) Cis- and trans- geometrical isomerism (c) R- and S- optical isomerism (d) Linkage isomerism
30. Consider the following reaction: Nb2S5 + 5HgO ⇌ Nb2O5 + 5HgS On the basis of the relative electronegativity and charges on the various ions, hard and soft character of the acids and bases, which one of the following is correct? (a) The products are favoured (b) The reactants are favoured (c) Nb2O5 is favoured, however the reaction does not proceed due to HgS (d) HgS formation is favoured, however the reaction does not proceed due to Nb2O5
31. Which one of the following is correct regarding addition of acetic acid to sulphuric acid, water and ammonia, respectively? (a) Acetic acid behaves as a base in sulphuric acid, weak acid in water and strong acid in ammonia (b) Acetic acid behaves as a weak acid in sulphuric acid, water and ammonia (c) Acetic acid behaves as a weak acid in water and strong acid in sulphuric acid and ammonia (d) Acetic acid behaves as strong acid in sulphuric acid and ammonia and as weak acid in water
32. What will happen, if a 1-0M solution of a weak acid is diluted to 0-01M at constant temperature? (a) Ka will increase (b) Degree of ionization will increase (c) pH will decrease by 2 units (d) [H+] will decrease to 0-01M
33. Consider the following statements regarding the ionic product of water: (where CH+ and COH- are the concentration of hydrogen and hydroxide ions of water, respectively and KW is the ionic product of water) 1. The value of KW at 25°C is 1×10-14 2. CH+ = COH- in pure water 3. KW increases with temperature 4. CH+ = KW1/2 for pure water Which of the statements given above are correct? (a) 1 and 2 only (b) 1 and 3 only (c) 2 and 4 only (d) 1, 2, 3 and 4
34. An aqueous solution contains 0.3 mol/litre of KHSO4 and 0.6 mol/litre of K2SO4. The pH of the solution will be (The pKa value for HSO4- is 2.0 and log 2.0 = 0.30) (a) 2-3 (b) 0-3 (c) 2-0 (d) 4-3
35. Which one of the following does NOT act as Buffer in its aqueous solution? (a) Borax (b) NH4HF2 (c) CH3COONa (d) NH3 + NH4Cl
36. Which one of the following is the correct form of Henderson's equation for calculating the pH of a weak acid solution containing its salt? (a) pH = pKa + log [acid]/[conjugate base] (b) pH = pKa + log [conjugate base]/[acid] (c) pH = pKa - log [acid]/[conjugate base] (d) pH = pKa - log [conjugate acid]/[base]
37. Which one of the following equations is used to get molarity (M) of a standard solution? (a) M = (Weight of solute in gm / Molecular weight of solute) × (1000 / Volume of solution (mL)) (b) M = (Weight of solute in gm / Equivalent weight of solute) × (1000 / Volume of solution (mL)) (c) M = (Volume of solute (mL) / Molecular weight of solute) × (1000 / Weight of solution (gm)) (d) M = (Volume of solute (mL) / Equivalent weight of solute) × (1000 / Weight of solution (gm))
UPSC Previous year question paper Geo scientist exam
38. Despite of being obtained in high purity, sodium thiosulphate is unsuitable as a primary standard. This is because: 1. CO2 present in ordinary distilled water may decompose it 2. It can be decomposed by bacterial action 3. It decomposes upon exposure to light Select the correct answer using the code given below: (a) 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) 1, 2 and 3
39. A sharp end point is NOT achieved during titration of boric acid against NaOH. The sharp end point can be observed (a) By addition of suitable Lewis acid to the solution (b) By using diphenylamine sulphonic acid as indicator (c) By addition of suitable organic polyhydroxy compounds (d) By using xylenol-orange as indicator
40. Which one of the following indicators is NOT used as acid-base indicator? (a) Methyl orange (b) Phenolphthalein (c) Murexide (d) Methyl red
41. At a specific temperature, the ratio of the mean kinetic energy of hydrogen to oxygen gas is (a) 1:16 (b) 1:8 (c) 1:4 (d) 1:1
42. The root mean square velocity of one mole of a monoatomic gas having molar mass M is urms. Which one of the following correctly represents the relation between the average kinetic energy of the gas (E) and urms ? urms = sqrt(3E/2M) urms = sqrt(2E/M) urms = sqrt(E/2M) urms = sqrt(E/3M)
43. Initially in a container having an ideal gas, all the molecules had the same translational energy of 6·0 × 10-21 J. After some time, due to random motion of the molecules, the energies of the molecules were distributed according to the Maxwell-Boltzmann distribution law. The final temperature of the system is (Given: k = 1·38 × 10-23 J K-1) (a) 289-72 K (b) 0-481 K (c) 481-1 K (d) 2-898 K
44. Which one of the following has the highest value of most probable speed ? (a) H2(g) at -73°C (b) CH4(g) at 27°C (c) N2(g) at 1027°C (d) O2(g) at 0°C
45. The root mean square velocity of gas A at 27°C was found to be equal to the root mean square velocity of gas B at 327°C. The ratio of molar mass of A to B is (a) 109 : 9 (b) 9 : 109 (c) 2 : 1 (d) 1 : 2
46. The Maxwell-Boltzmann distribution curves of oxygen, nitrogen, carbon dioxide and methane gases were plotted at 300 K and following graph was obtained [Figure: Graph] Identify the curves (1, 2, 3 and 4) with the appropriate gases and select the correct answer (a) 1-CO2, 2-O2, 3-N2, 4-CH4 (b) 1-CH4, 2-N2, 3-O2, 4-CO2 (c) 1-CH4, 2-CO2, 3-O2, 4-N2 (d) 1-CO2, 2-N2, 3-O2, 4-CH4
47. A steel vessel contains a mixture of H2 and O2 in a 2 : 1 molar ratio at a constant temperature T and pressure p. If the volume of H2 gas collected in 10 min is 15 mL at the same T and p, what will be the volume of O2 gas collected in 20 min at the same T and p ? (a) 3-8 mL (b) 1-9 mL (c) 3-2 mL (d) 5-6 mL
48. The average velocity of a gas molecule of O2 at 25°C and 1 bar is 400 m s-1 and its collision frequency is 2·0 × 109 s-1. The mean free path and the average time between collisions are respectively (a) 500 nm and 1·25 × 10-5 s (b) 200 nm and 5·0 × 10-10 s (c) 50 nm and 2·0 × 1010 s (d) 200 nm and 5·0 × 1010 s
UPSC Previous year question paper Geo scientist exam
49. Which of the following is/are correct when 131 g of zinc is allowed to react with hydrochloric acid at 27°C ? (Given : Molar mass of Zn is 65.4 g mol-1 and R = 8.3 J K-1 mol-1) 1. The reaction involved is Zn + 2HCl → ZnCl2 + H2 2. When the reaction mixture is kept in a closed vessel of fixed volume, work done is zero 3. When the reaction mixture is kept in an open vessel, the reaction mixture does 4-98 kJ of work driving back the atmosphere Select the answer using the code given below : (a) 1 and 2 only (b) 3 only (c) 1 and 3 only (d) 1, 2 and 3
50. A sample of an ideal gas changes its volume from 3-00 L to 6-00 L against an external pressure of 2-50 atm and simultaneously absorbs 1000 J of heat. The change in internal energy of the system is (1 L atm = 101·325 J) (a) -760 J (b) 240 J (c) -240 J (d) 760 J
51. Match List I with List II and select the correct answer using the code given below the Lists : List I (Property/ Variable) A. U B. Hm C. Cp,m D. Cp List II (Intensive/ Extensive and SI unit) 1. Intensive, J mol-1 2. Extensive, J 3. Extensive, J K-1 4. Intensive, J mol-1 K-1 Code : A B C D (a) 2 4 1 3 (b) 2 1 4 3 (c) 3 1 4 2 (d) 3 4 1 2
52. Consider the reversible isothermal expansion of 5-00 mol of an ideal gas from 0-500 dm3 to 1-500 dm3 at 300 K. (Given: R = 8·314 J K-1 mol-1 and log 3 = 0.4771) Which of the following are true for the above system ? 1. ΔU = 0 2. ΔH = 0 3. w = -13.7 kJ 4. q = 13.7 kJ Select the answer using the code given below : (a) 1 and 2 only (b) 1, 2 and 3 only (c) 3 and 4 only (d) 1, 2, 3 and 4
53. Sphalerite (ZnS) is the sulphide ore of zinc. Given: ΔfH298° (in kJ mol-1) for sphalerite, ZnO(s) and SO2(g) are -206, -348 and -296, respectively, the ΔrH298° (in kJ mol-1) for the roasting of sphalerite ore will be (a) -850 (b) 438 (c) -438 (d) -258
54. In a porcelain dish exposed to air at 27°C 1-22 g of benzoic acid is burned, releasing 31,700 J of heat. The enthalpy change (ΔH) and internal energy change (ΔU) for the process are, respectively (Given : Molar mass of benzoic acid is 122 g mol-1) (a) -31,688 J and -31,700 J (b) -31,700 J and -30,453 J (c) -31,700 J and -31,637 J (d) -31,700 J and -31,688 J
55. Which of the following statements are correct ? 1. The rate of change of ΔH° with respect to temperature is equal to ΔCp° 2. For a reaction involving only ideal gases ΔCp° is independent of temperature 3. ΔcH298° - ΔcU298° = 0 for glucose 4. When a substance is in its thermodynamic standard state, the substance must be at 25°C Select the answer using the code given below : (a) 1 and 2 (b) 2 and 3 (c) 1 and 3 (d) 3 and 4
56. Which one of the following statements must be true for an endothermic reaction to be spontaneous under standard conditions at constant pressure and at a certain temperature T ? (a) ΔS° must be positive and greater than ΔH°/T (b) ΔS° must be positive and less than ΔH°/T (c) ΔS° must be negative and greater than ΔH°/T (d) ΔS° must be negative and less than ΔH°/T
57. Suppose the coldest reservoir we have at hand is at 12°C. If we want a heat engine that is at least 90% efficient, the minimum temperature of the required hot reservoir should be (a) 2577 K (b) 2577°C (c) 100°C (d) 373 K
UPSC Previous year question paper Geo scientist exam
58. Which of the following transformations will show positive entropy change ? 1. 1 mol of H2O (l, 273 K, 101-325 kPa) → 1 mol of H2O (s, 273 K, 101-325 kPa) 2. 1 mol of H2O (l, 273 K, 101-325 kPa) → 1 mol of H2O (l, 373 K, 101-325 kPa) 3. 1 mol of H2O (l, 373 K, 101-325 kPa) → 1 mol of H2O (g, 373 K, 101-325 kPa) 4. 1 mol of H2O (g, 373 K, 10-1325 kPa) → 1 mol of H2O (g, 373 K, 101-325 kPa) Select the correct answer using the code given below : (a) 1 and 2 only (b) 2 and 3 (c) 1, 2 and 4 (d) 3 and 4
59. The correct value for the non-expansion work that can be obtained from the combustion of 2-00 mol of methane under standard conditions at 300 K is Given that : ΔrS° = -243 J K-1 mol-1, ΔfH°(CH4, g) = -75 kJ mol-1, ΔfH°(CO2, g) = -393 kJ mol-1, ΔfH°(H2O, l) = -286 kJ mol-1 (a) -1760 kJ (b) -1634 kJ (c) 144 kJ (d) -817 kJ
60. Which one of the following graphs correctly represents the variation of Gibbs energy with pressure ? [Figure: Graphs a, b, c, d] (a) Gas, Liquid, Solid (b) Solid, Liquid, Gas (c) Gas, Liquid, Solid (d) Liquid, Solid, Gas
61. Consider the following statements regarding the criteria for spontaneous processes in closed systems : 1. If a system is isolated, its entropy cannot decrease 2. If S of a closed system is fixed and no work is done, U cannot increase 3. dA ≤ 0 (simple closed system, T and V constant) Which of the statement(s) given above is/are correct ? (a) 1 and 2 only (b) 1 only (c) 2 and 3 only (d) 1, 2 and 3
62. At 300 K, Z-2- butene isomerises to E-2- butene with ΔGr° = -3.44 kJ mol-1 [Figure: Reaction] A catalyst for isomerisation is added to a vessel that is kept at 300 K along with a small amount of Z- 2- butene. The mole fraction of E- 2- butene in the vessel when equilibrium is reached is : (Given : R = 8.31 J K-1 mol-1 and ln 2 = 0.69) (a) 0-23 (b) 0-34 (c) 0-56 (d) 0-80
63. The osmotic pressure of 0-01 mol dm-3 solutions of the following substances was measured at 300 K : 1. Acetic acid in benzene 2. Acetic acid in water 3. NaCl in water 4. Glucose in water Which one of the following is the correct order (increasing) of osmotic pressure of the above solutions ? (a) Glucose in water, acetic acid in water, acetic acid in benzene, NaCl in water (b) Glucose in water, acetic acid in benzene, acetic acid in water, NaCl in water (c) Acetic acid in benzene, glucose in water, acetic acid in water, NaCl in water (d) NaCl in water, acetic acid in water, acetic acid in benzene, glucose in water
64. 1 mol benzene (p°benzene = 6.0 kPa) and 2 mol toluene (p°toluene = 4.8 kPa) are mixed to form a solution. Which one of the following statements regarding the above solution is NOT correct ? (a) Total vapour pressure of the solution is 5.2 kPa (b) Mole fraction of vapours of benzene above the liquid mixture is 0-33 (c) The solution will follow Raoult's law (d) The solution will not show any appreciable change in volume
UPSC Previous year question paper Geo scientist exam
65. The correct labels for the given plots of vapour pressure against the mole fraction of solute is [Figure: Graph] (a) 1-Ideal solution (Raoult), 2-Ideal solution (Henry), 3-Real solution (b) 1-Ideal solution (Henry), 2-Real solution, 3-Ideal solution (Raoult) (c) 1-Ideal solution (Henry), 2-Ideal solution (Raoult), 3-Real solution (d) 1-Real solution, 2-Ideal solution (Henry), 3-Ideal solution (Raoult)
66. A polymer X is dissolved in a suitable solvent and the osmotic pressure (π) of solutions of various concentrations (c) is measured at 27°C. The intercept of a plot of (π / (N m-2)) / (c / (g dm-3)) against c / (g dm-3) is found to be 25. The molar mass of X in kg mol-1 is (Given: R = 8.314 J K-1 mol-1) (a) 100 (b) 997 (c) 9976 (d) 99768
67. Which of the following statements regarding the colligative properties of solutions containing a non-volatile electrolyte are correct ? 1. The vapour pressure of the pure solvent is higher than that of the solution 2. The vapour pressure of the pure solvent is less than that of the solution 3. Only solute molecules solidify at the freezing point 4. Only solvent molecules solidify at the freezing point Select the answer using the code given below : (a) 1 and 3 (b) 2 and 4 (c) 1 and 4 (d) 2 and 3
68. Which one among the following is NOT a factor affecting the boiling point elevation constant ? (a) The molar mass of the solute (b) The molar mass of the solvent (c) The enthalpy of vaporization of the solvent (d) The boiling point of the solvent
69. The Henry's Law constant (for the dissolution of gases in liquids) has the unit of (a) Pa (b) kg mol-1 (c) mL (d) K kg mol-1
70. When a conductivity cell is filled with a 0-001 mol L-1 solution of NaNO3 its resistance is found to be 6000 Ω The molar conductance of the solution is given as 120 S cm2 mol-1. The cell constant of the given conductivity cell is (a) 0-72 cm-1 (b) 1-0 cm-1 (c) 0-072 cm-1 (d) 2-0 cm-1
71. The Λm∞ values for calcium acetate, sodium acetate and sodium iodide solutions are 202, 91 and 127 S cm2 mol-1 respectively at 298 K. The Λm∞ for calcium iodide is (a) 238 S cm2 mol-1 (b) 274 S cm2 mol-1 (c) 365 S cm2 mol-1 (d) 456 S cm2 mol-1
72. A potential difference of 4-5 V is applied across two electrodes placed 10-0 cm apart in a dilute solution of a salt of X at 27°C. How far would the X- ion be expected to move in 2 hours ? Given: λ(X-) = 80 S cm2 mol-1, F = 96,500 C mol-1 (a) 2-7 cm (b) 5-9 cm (c) 13-2 cm (d) 4-5 cm
73. The conductivity of a saturated solution of AgCl was found to be 1.8 × 10-6 S cm-1 at 25°C after correction for the conductivity of pure water. What is the molar conductivity of Cl- ions at infinite dilution, if the molar conductivity of Ag+ ions at infinite dilution is 62.0 S cm2 mol-1 and the solubility product of AgCl is 1.69 × 10-10 M2 at 25°C ? (a) 76-5 S cm2 mol-1 (b) 200-4 S cm2 mol-1 (c) 63-4 S cm2 mol-1 (d) 138-4 S cm2 mol-1
74. Consider the following statements regarding two electrolytes 'X' and 'Y' whose molar conductivities increase by a factor of 20 and 1-5 respectively, on dilution : Statement- 1 : 'X' is a strong electrolyte and 'Y' is a weak electrolyte Statement- 2 : For weak electrolytes the increase in molar conductivity is due to the increase in degree of dissociation of the electrolyte on dilution Which one of the following is correct in respect of above statements ? (a) Both statement 1 and statement 2 are true and statement 2 is the correct explanation of statement 1 (b) Both statement 1 and statement 2 are true and statement 2 is not the correct explanation of statement 1 (c) Statement 1 is true but statement 2 is false (d) Statement 1 is false but statement 2 is true
UPSC Previous year question paper Geo scientist exam
75. Debye- Hückel theory explains the dependence of the conductance of strong electrolytes on their concentration. This theory also explains the other properties of ionic solutions. List I gives the conditions for conductance of aqueous electrolytic solutions, while List II provides the names of corresponding effects. Match List I with List II and select the correct answer using the code given below the lists : List I List II A. Ionic atmosphere B. Solvated ionic atmosphere C. Increased conductance under high potential D. Increased conductance at high frequency Code :
76. What molality of NaCl is needed so that it has the same ionic strength as 0.100 m Ca3(PO4)2 ? (a) 0.300 m (b) 0.500 m (c) 1.00 m (d) 1.500 m
77. Match List-I with List-II and select the correct answer using the code given below the lists : List I (conductoretic titration) A. HCl vs KOH B. HCl vs NH4OH C. CH3COOH vs NaOH D. Oxalic acid vs NaOH [Figures 1, 2, 3, 4] Code : A B C D (a) 3 2 4 1 (b) 3 4 2 1 (c) 1 2 4 3 (d) 1 4 2 3
78. Consider the following statements regarding transport number: Statement-1: Cd2+ shows negative transport number in highly concentrated solutions of CdI2 Statement-2: Transport numbers of ions are directly proportional to their speeds Which of the statement(s) given above is/are correct? (a) Neither 1 nor 2 (b) Both 1 and 2 (c) 1 only (d) 2 only
79. During the titration of 50.0 mL of a 0.10 mol L-1 solution of acetic acid (Ka = 1.8 × 10-5) with a 0.10 mol L-1 solution of sodium hydroxide, the specific conductance after addition of 50.0 mL of sodium hydroxide will be: (Given: λCH3COO- = 40.9 × 10-4 S m2 mol-1, λNa+° = 50.1 × 10-4 S m2 mol-1) (a) 0.455 S m-1 (b) 0.910 mS m-1 (c) 0.455 mS m-1 (d) 0.910 S m-1
80. In the determination of the transport number of Li+ ion by the moving boundary method, a 0.10 M solution of LiCl was taken in a cell having uniform area of cross section of 1.0 cm2. At the end of the experiment the boundary moved by 2.0 cm and 0.09 g of silver was deposited on the cathode of a silver coulometer. The transference number of Li+ ion is (Given: Faraday = 96,500 C mol-1, Atomic mass of Ag = 108) (a) 0-24 (b) 0-40 (c) 0-60 (d) 0-76
81. The correct decreasing order of basicity of the following anions is [Figure: Anions I, II, III] (a) II > III > I (b) I > III > II (c) III > I > II (d) II > I > III
82. The types of hybridization exhibited by the carbon atoms in the given compound are [Figure: Compound] (a) sp2 and sp3 only (b) sp2 and sp only (c) sp and sp3 only (d) sp, sp2 and sp3
UPSC Previous year question paper Geo scientist exam
83. Which one of the following molecular orbitals will be formed by combination of the two 2p orbitals as shown below? [Figure: Orbitals] (a) bonding π molecular orbital (b) bonding σ molecular orbital (c) antibonding π* molecular orbital (d) antibonding σ* molecular orbital
84. Which one of the following compounds can be most readily converted into carbon free radical ? [Figure: Compounds I, II, III, IV] (a) I (b) II (c) III (d) IV
85. Which one of the following is correct for the molecules given below ? [Figure: Molecules I, II] (a) Both I and II are chiral (b) I is chiral and II is achiral (c) I is achiral and II is chiral (d) Both I and II are achiral
86. Predict the relationship between the pair of compounds given below : [Figure: Compounds] (a) Enantiomers (b) Identical (c) Diastereomers (d) Constitutional isomers
87. The correct IUPAC name of the given compound is [Figure: Compound] (a) (1S, 2R)-2-Amino-1,2- diphenylethan-1-ol (b) (1R, 2S)-2-Amino-1,2- diphenylethan-1-ol (c) (1S, 2S)-2-Amino-1,2- diphenylethan-1-ol (d) (1R, 2R)-2-Amino-1,2- diphenylethan-1-ol
88. The relationship between the compounds given below is [Figure: Compounds] (a) Optical isomers (b) Constitutional isomers (c) Geometrical isomers (d) Regioisomers
89. Which one of the following compounds has the highest preference to exist as gauche conformer ? 1,2- Dichloroethane I 1,2- Dibromoethane II 1,2- Difluoroethane III n- Butane IV (a) I (b) II (c) III (d) IV
90. Which one among the following pairs is NOT correctly matched ? Statement Predominant pathway (a) Cyclohexyl bromide reacts with sodium ethoxide in ethanol (b) tert- Butyl bromide reacts with sodium ethoxide in ethanol (c) The strength of the nucleophile is important in determining rate (d) Rearrangements are possible in product formation
91. In an experiment, the rate of racemization of 2-iodooctane by sodium iodide (Na131I) in acetone was compared with the rate of incorporation of radioactive iodine into 2-iodooctane [Figure: Reaction] If we assume that each incorporation proceeds stereospecifically with inversion of configuration then we can conclude that (a) There will not be any observable racemization (b) The rate of racemization will be equal to the rate of incorporation of radioactive iodine (c) The rate of racemization will be twice the rate of incorporation of radioactive iodine (d) The rate of incorporation of radioactive iodine will be twice the rate of racemization
92. The number of methyl groups at the axial and equatorial positions, respectively in the most stable conformation of the major product formed in the following reaction are [Figure: Reaction] (a) Three and one (b) Two and two (c) One and three (d) Zero and four
93. The major products [X] and [Y] formed in the following reaction sequence are [Figure: Reaction] [Figure: Options a, b, c, d]
94. The product(s) formed due to neighbouring group participation in the following reaction is/are [Figure: Reaction] [Figure: Options I, II, III, IV] (a) I and III (b) II and IV (c) Only II (d) III and IV
95. Consider the following statements about the reactivity of compounds I-IV : [Figure: Compounds] where OPNB is p- nitrobenzoate 1. Compound I undergoes solvolysis in aqueous acetone slower than II 2. Compound I undergoes solvolysis in aqueous acetone faster than II 3. Compound III reacts with KI slower than IV 4. Compound III reacts with KI faster than IV Which of the statements given above are correct ? (a) 1 and 3 (b) 1 and 4 (c) 2 and 3 (d) 2 and 4
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96. The major products [X] and [Y] formed in the following reactions are [Figure: Reactions] [Figure: Options a, b, c, d]
97. Consider the following statements with respect to compounds A and B [Figure: Compounds A, B] 1. The dihedral angle between Cl and H on adjacent carbons in compound A is 180° 2. The dihedral angle between Cl and H on adjacent carbons in compound B is 0° 3. Compound A undergoes HCl elimination about 8 times faster than compound B How many of the above statement(s) is/are correct? (a) Only one (b) Only two (c) All three (d) None
98. Which one of the following statements regarding the given reaction sequence is correct? [Figure: Reaction] [Figure: Products I, II, III] (a) The major product of the reaction is I and is called Hofmann product (b) The major product of the reaction is II and is called Zaitsev product (c) The major product of the reaction is III and is called Hofmann product (d) The major product of the reaction is III and is called Zaitsev product
99. Which one of the following alkyl bromides will give exclusively one terminal mono- substituted alkene upon dehydrobromination by an E2 process ? (a) 3-bromo-3-methylpentane (b) 3-bromo-2-methylpentane (c) 2-bromo-2,3-dimethylbutane (d) 2-bromo-3,3-dimethylbutane
100. The mechanism of the following reaction involves the sequential conversion of [Figure: Reaction] (a) 1° carbocation to 3° carbocation to 3° carbocation (b) 1° carbocation to 2° carbocation to 2° carbocation (c) 1° carbocation to 2° carbocation to 3° carbocation (d) 1° carbocation to 3° carbocation to 2° carbocation
101. A potential energy diagram is shown below for the E1 mechanism of indicated reaction [Figure: Reaction and Graph] By applying Hammond's postulate to the potential energy diagram for this reaction, which one of the following statements is correct ? (a) The structure of transition state 2 is more carbocation-like than transition state 4 (b) The structure of transition state 2 is less carbocation-like than transition state 4 (c) The structure of transition state 2 resembles 1 more than it resembles 3 (d) The structure of transition state 4 resembles 5 more than it resembles 3
102. The major product formed in the following reaction is [Figure: Reaction]
103. Consider the catalytic hydrogenation of compounds P, Q and R as indicated in the table. The number of carboxylic rings and π-bonds present in compounds P, Q and R have been indicated. Complete the table by identifying the missing positions described by notations W, X, Y and Z [Figure: Compounds a, b, c, d] [Table] (a) W = C40H82, X = C10H22, Y = 3 and Z = 1 (b) W = C40H80, X = C10H20, Y = 2 and Z = 2 (c) W = C40H76, X = C10H22, Y = 0 and Z = 4 (d) W = C40H78, X = C10H16, Y = 1 and Z = 3
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104. The major product formed in the following reaction is [Figure: Reaction] [Figure: Options a, b, c, d]
105. Consider the following statements : 1. The anti-addition of a symmetric reagent to a symmetric cis-alkene gives racemic product 2. The anti-addition of a symmetric reagent to a symmetric trans-alkene gives racemic product 3. The syn-addition of a symmetric reagent to a symmetric cis-alkene gives racemic product 4. The syn-addition of a symmetric reagent to a symmetric trans-alkene gives meso product How many of the above statement(s) is/are true ? (a) Only one (b) Only two (c) Only three (d) All of the above
106. Which one of the following statements is correct regarding the outcome of the indicated reaction ? [Figure: Reaction] (a) At low and high temperature, 1,4-addition product is the major one (b) At low and high temperature, 1,2-addition product is the major one (c) At low temperature, 1,2-addition product is the major one while at high temperature, 1,4-addition product is the major one (d) At low temperature, 1,4-addition product is the major one while at high temperature, 1,2-addition product is the major one
107. The total number of 1,4-addition reactions involved in the synthesis of target molecule [X] using the indicated starting material is/are [Figure: Reaction] (a) One (b) Two (c) Three (d) Four
108. The major product formed in the following reaction sequence is [Figure: Reaction] [Figure: Options a, b, c, d]
109. The major product formed in the following reaction is [Figure: Reaction] [Figure: Options a, b, c, d]
110. Consider the following statements : 1. 4-Chloro-3-nitroacetophenone reacts with sodium methoxide in methanol slower than 4-chloro-3- nitrotoluene 2. 4-Chloro-3-nitroacetophenone reacts with sodium methoxide in methanol faster than 4-chloro-3- nitrotoluene 3. 1-Bromo-2,4-dinitrobenzene reacts with sodium methoxide in methanol faster than 1,4-dibromo-2-nitrobenzene 4. 1-Bromo-2,4-dinitrobenzene reacts with sodium methoxide in methanol slower than 1,4-dibromo-2- nitrobenzene Which of the statements given above are correct ? (a) 1 and 3 (b) 1 and 4 (c) 2 and 3 (d) 2 and 4
111. The most reasonable cyclohexadienyl cation intermediate involved in the mechanism of following isomerization reaction is [Figure: Reaction] [Figure: Options a, b, c, d]
112. Which one of the following reactions does NOT follow the addition- elimination pathway ? [Figure: Reactions a, b, c, d]
113. The number of sp3 and sp2 carbons, respectively, present in the Meisenheimer complex, formed in the following reaction are [Figure: Reaction] (a) Three and six (b) Four and five (c) Five and four (d) Six and three
114. The major products [X] and [Y] formed in the following reactions are [Figure: Reactions] [Figure: Options a, b, c, d]
115. Which one of the following 1,2- diols is the least reactive for acid catalyzed pinacol- pinacolone rearrangement ? [Figure: Options a, b, c, d]
116. The reactive intermediates 1-4 that are likely to be formed in the given reaction are shown below : [Figure: Reaction and Intermediates] What is the sequence of their formation in the mechanism of the above reaction ? (a) 3 → 2 → 1 → 4 (b) 3 → 4 → 1 → 2 (c) 1 → 3 → 4 → 2 (d) 1 → 4 → 3 → 2
117. The relative order of reactivity for solvolysis of the following compounds in acetic acid is [Figure: Compounds I, II, III] (a) III < I < II (b) I < III < II (c) II < I < III (d) II < III < I
118. Which one of the following statements about the indicated reaction is correct ? [Figure: Reaction] [Figure: Products I, II] (a) The major product of the reaction is I and is achiral (b) The major product of the reaction is I and is chiral (c) The major product of the reaction is II and is chiral (d) The major product of the reaction is II and is achiral
119. The major product formed in Reaction I and Reaction II are Reaction I : (1R,2R)- 2- bromocyclohexan- 1- ol H+ Reaction II : (1S,2R)- 2- bromocyclohexan- 1- ol H+ (a) Reaction I : (1S,2S)- 1,2- dibromocyclohexane Reaction II : (1S,2S)- 1,2- dibromocyclohexane (b) Reaction I : (1R,2S)- 1,2- dibromocyclohexane Reaction II : (1R,2S)- 1,2- dibromocyclohexane (c) Reaction I : (1R,2R)- 1,2- dibromocyclohexane Reaction II : (1R,2S)- 1,2- dibromocyclohexane (d) Reaction I : (1R,2R)- 1,2- dibromocyclohexane Reaction II : (1R,2R)- 1,2- dibromocyclohexane
120. In the solvolysis reactions of I and II in aqueous ethanol, which one of the following statements is true ? [Figure: Compounds I, II, III, IV] (a) I reacts faster than II and the major product formed is III (b) I reacts faster than II and the major product formed is IV (c) II reacts faster than I and the major product formed is III (d) II reacts faster than I and the major product formed is IV
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