UPSC Combined Geo-Scientist (Preliminary) Examination Chemistry 2024
1. Which among the following principal quantum numbers has/have five degenerate d-orbitals?
(a) 2
(b) 3 only
(c) 4 only
(d) Both 3 and 4
2. Which one of the following statements related to radial distribution plots for hydrogen atom is not correct?
(a) Most probable radius varies as 3s > 3p > 3d.
(b) Most probable radius varies as 1s < 2s < 3s.
(c) Most probable radius varies as 2p < 3p.
(d) Most probable radius varies as 3s < 3p < 3d.
3. Which one of the following sets of quantum numbers represents the highest energy state?
| n | l | mₗ | mₛ |
|---|---|---|---|
| (a) 4 | 0 | 0 | +½ |
| (b) 3 | 0 | 0 | −½ |
| (c) 3 | 1 | 1 | +½ |
| (d) 3 | 2 | 1 | −½ |
4. Which one of the following groups of elements contains true metals only?
(a) Carbon, boron, silicon
(b) Magnesium, aluminium, selenium
(c) Boron, carbon, nitrogen
(d) Sodium, thallium, bismuth
5. The electronic configuration of an element A is [Xe]4f¹5d¹6s² and that of an element B is [Xe]4f³6s². The elements A and B are
(a) transition element and lanthanide, respectively
(b) lanthanide and actinide, respectively
(c) transition element and actinide, respectively
(d) both lanthanides
6. The physical and chemical properties of elements are periodic functions of their
(a) atomic weight
(b) atomic size
(c) atomic number
(d) atomic shape
7. Which one of the following represents the correct order of ionic radii among Y³⁺, La³⁺, Eu³⁺ and Lu³⁺?
(a) Y³⁺ < La³⁺ < Eu³⁺ < Lu³⁺
(b) Lu³⁺ < Eu³⁺ < La³⁺ < Y³⁺
(c) Eu³⁺ < La³⁺ < Lu³⁺ < Y³⁺
(d) Lu³⁺ < Y³⁺ < Eu³⁺ < La³⁺
8. Using Slater's rule, the effective nuclear charge experienced by 3d-electron in titanium (atomic number 22) is
(a) 22.0
(b) 7.53
(c) 5.14
(d) 3.65
9. Atomic size of nitrogen is less than carbon atom, yet carbon shows maximum catenation property while nitrogen does not. The reason for this is
(a) lone pair-lone pair repulsions in N=N single bond make the bond weaker to allow catenation
(b) catenation is not dependent on atomic size
(c) carbon has poor multiple bonds formation ability
(d) nitrogen exists as an inert gas and therefore does not react
10. Consider the following statements :
1. Sulfur has a higher ionization energy than phosphorus.
2. Sulfur has a lower ionization energy than phosphorus.
3. Sulfur has a lower electron affinity than chlorine.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) 1 and 3
(d) 2 and 3
11. Which one of the following represents the correct order of bond angle among H₂O, H₂Te, H₂Se and H₂S?
(a) H₂O > H₂S > H₂Se > H₂Te
(b) H₂S > H₂Se > H₂O > H₂Te
(c) H₂O > H₂Se > H₂S > H₂Te
(d) H₂Te > H₂O > H₂S > H₂Se
12. Consider the following statements :
1. On moving from left to right in the periodic table, the metallic character of elements decreases.
2. On moving from left to right in the periodic table, the oxides of elements become less basic.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
13. Carbon is able to show allotropic forms due to
(a) its smaller size
(b) its higher electronegativity
(c) its higher ionization enthalpy and unavailability of d-orbitals
(d) catenation and pπ - pπ bond formation
14. A neutral atom of an element has two K, eight L and five M electrons. What will be the total number of p-electrons in the element?
(a) 9
(b) 8
(c) 7
(d) 6
15. Consider the following statements :
Statement-1 :
An aqueous solution of NaH₂PO₄ is acidic and that of Na₂HPO₄ is basic in nature.
Statement-2 :
An equimolar mixture of NaH₂PO₄ and Na₂HPO₄ acts as a buffer.
Which one of the following is correct with respect to the above statements?
(a) Both Statement-1 and Statement-2 are true and Statement-1 is not the correct explanation of Statement-2
(b) Both Statement-1 and Statement-2 are true and Statement-1 is the correct explanation of Statement-2
(c) Statement-1 is true but Statement-2 is false
(d) Statement-1 is false but Statement-2 is true
16. In SO₃ , one p -orbital and two d -orbitals are used in S = O π -bond formation. However, all S = O bond lengths are identical. This is due to
(a) involvement of equivalent hybrid orbitals in π -bonding
(b) considerable polarity in bonds
(c) delocalization of π -bonds in the molecule
(d) ionic covalent resonance in the molecule
17. Consider the following statements regarding NF₃ :
1. NF₃ has bond angle value much lower than tetrahedral bond angle.
2. NF₃ is a good Lewis base.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
18. Which one of the following reactions is not possible between diborane and ammonia?
(a) B₂H₆ + NH₃ (Excess) Low T B₂H₆·2NH₃
(b) B₂H₆ + NH₃ (Excess) High T (BN)x
(c) B₂H₆ + 2NH₃ RT Aqueous medium B₄H₁₀ + N₂ + 4H₂
(d) B₂H₆ + 2NH₃ High T B₃N₃H₆
19. For ZnS , a radius ratio (r(Zn²⁺) / r(S²⁻)) of 0.52 suggests a coordination number, of 6 for both cation and anion. However, in reality, ZnS adopts a coordination number of 4:4. This is because
(a) ZnS is a true covalent compound
(b) ZnS is an ionic compound with considerable covalency
(c) Zn²⁺ is too small to occupy octahedral holes
(d) S²⁻ ions are too large to provide higher coordination number to Zn²⁺
20. Theoretically calculated lattice energy (using Born-Lande equation) of hypothetical molecule NaCl₂ is −2180 kJ/mol while that of NaCl is −755 kJ/mol . (Both the molecules are assumed to be formed from elements in their standard states.) Yet NaCl is a stable molecule while NaCl₂ does not exist. The reason for this is
(a) dissociation energy of Cl₂ molecule is too high
(b) second ionization energy of Na metal is too high
(c) electron affinity of Cl atom is too low
(d) Born-Lande equation cannot predict the correct lattice energy of these molecules
21. The solubility of an ionic compound in a solvent depends on
(a) lattice enthalpy only
(b) solvation enthalpy only
(c) lattice enthalpy and solvation enthalpy both
(d) ionization enthalpy of metal
22. Consider the following statements regarding Frenkel defect in solids :
Statement- 1 :
Compounds having Frenkel defects have some covalent character.
Statement- 2 :
Compounds having Frenkel defects have small positive ions and large negative ions, where small positive ions are highly polarizing and large negative ions are readily polarized.
Which one of the following is correct with respect to the 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
23. Two types of F atoms in (CH₃)PF₄ are indistinguishable while in (CH₃)₂PF₃ , equatorially placed F atom is distinguishable from apical F atom with the help of ¹⁹F NMR spectroscopy. The reason for the same is
(a) (CH₃)PF₄ has a square pyramidal geometry while (CH₃)₂PF₃ has a trigonal bipyramidal geometry
(b) (CH₃)PF₄ has all equivalent hybrid orbitals but (CH₃)₂PF₃ has non- equivalent hybrid orbitals
(c) inductive effect of methyl groups is higher in (CH₃)₂PF₃ than in (CH₃)PF₄
(d) two methyl groups pose higher rigidity in the molecule to allow pseudorotation in (CH₃)₂PF₃
24. The bond angle in H₂O molecule is 104.5° . The p -character in nonbonding set of orbitals will be [where cos(104.5°) = −0.25]
(a) 20%
(b) 70%
(c) 75%
(d) 80%
25. The wave function Ψ = Ψ_cov + λΨ_(H⁺H⁻) + λΨ_(H⁻H⁺) expresses the phenomenon of
(a) vibration
(b) resonance
(c) conjugation
(d) orbital
26. Werner confirmed the presence of primary and secondary valencies in the coordination compounds CoCl₃·6NH₃ , CoCl₃·5NH₃ and CoCl₃·4NH₃ by
(a) treating cold aqueous solutions of cobalt complexes with excess of silver nitrate solution
(b) treating cold aqueous solutions of cobalt complexes with excess of barium nitrate solution
(c) treating cold aqueous solutions of cobalt complexes with excess of barium chloride solution
(d) treating cold aqueous solutions of cobalt complexes with excess of sodium nitrate solution
27. Which one among the following chelate rings will be more stable?
(a) Four-membered chelate ring
(b) Five-membered chelate ring
(c) Six-membered chelate ring
(d) Seven-membered chelate ring
28. Which one of the following is the correct IUPAC name of Li[AlH₄] ?
(a) Lithium aluminium hydride
(b) Lithium aluminium tetrahydride
(c) Lithium tetrahydridoaluminate(III)
(d) Lithium tetrahydroaluminate(III)
29. Consider the following reaction :
[Co(NH₃)₄Cl₂]⁺ + Cl⁻ → [Co(NH₃)₃Cl₃] + NH₃
How many isomers of the product complex are possible for the above reaction?
(a) 1
(b) 2
(c) 3
(d) 5
30. The effective atomic number of K₄[Fe(CN)₆] complex is
(a) 34
(b) 35
(c) 36
(d) 38
31. The formula for the coordination compound amminediaquachloridoplatinum(IV) tetrachlorodoplatinate(II) is
(a) [PtCl(NH₃)(H₂O)₂][PtCl₄]
(b) [PtCl(NH₃)(H₂O)₂]₂[PtCl₄]₃
(c) [PtCl(NH₃)(H₂O)₂]₃[PtCl₄]₂
(d) [PtCl(NH₃)(H₂O)₂]₂[PtCl₄]
32. How many millilitres of 0.25 M solution of H₂SO₄ will react with 10 mL of 0.25 M solution of NaOH?
(a) 1 mL
(b) 2.5 mL
(c) 5 mL
(d) 10 mL
33. Which one of the following represents the correct order of acidity among CO₂ , SO₂ and SO₃ ?
(a) SO₃ > SO₂ > CO₂
(b) SO₂ > SO₃ > CO₂
(c) SO₂ > CO₂ > SO₃
(d) CO₂ > SO₂ > SO₃
34. Which of the following statements regarding Ostwald's dilution law is/are not correct? (Where α = degree of dissociation, k = equilibrium constant for dissociation, c = concentration of solution)
1. Activity coefficients are taken as unity.
2. Ostwald's law is valid for strong electrolytes.
3. One may conclude α = √(k/c) .
Select the correct answer using the code given below.
(a) 1 only
(b) 2 only
(c) 1 and 3
(d) 2 and 3
35. Which one of the following statements is correct?
(a) Water is strong electrolyte.
(b) The value of ionic product of water varies with temperature.
(c) The concentrations of H⁺ and OH⁻ in 10⁻⁵ M HCl solution are same.
(d) The ionization constant and ionic product of water are same.
36. The pH of a buffer solution containing 6.0 mL of CH₃COOH (0.2 M) and 4.0 mL of CH₃COONa (0.2 M) solutions will be approximately [where pKₐ(CH₃COOH) = 4.76 ; log 2 = 0.30 , log 3 = 0.48 ]
(a) 6.0
(b) 5.13
(c) 4.58
(d) 2.46
37. Which one of the following does not represent a correct expression for hydrolysis constant for the equilibrium reaction A⁻ + H₂O ⇌ OH⁻ + HA⁻ ?
(a) Kₕ = [OH⁻][HA] / [A⁻]
(b) pKₕ = pKw − pKₐ
(c) Kₕ = Kw / Kₐ
(d) Kₕ = [OH⁻][HA]
38. Which one among the following compounds does not form primary standard solution?
(a) Na₂CO₃
(b) NaOH
(c) ZnO
(d) Potassium hydrogen phthalate
39. While performing the titration of KMnO₄ with clear Mohr's salt solution, a student obtained brown precipitate in the conical flask instead of a colourless solution, much before the end point was reached. What could be the possible source of error?
(a) Reaction mixture was not heated to 60°C
(b) Fe²⁺ in the Mohr's salt solution hydrolyzed to precipitate brown hydroxide
(c) Reaction medium was not made acidic
(d) Too large quantity of KMnO₄ had been added to the Mohr's salt solution
40. In which one of the following titrations are metal-ion indicators used?
(a) Acid-base titration
(b) Precipitation titration
(c) Complexometric titration
(d) Redox titration
41. The total kinetic energy of 2 moles of an ideal gas at 300 K is approximately (where R = 8.3 J K⁻¹ mol⁻¹ )
(a) 1.25 × 10⁻²⁰ J
(b) 6.3 × 10⁻²¹ J
(c) 7.5 × 10³ J
(d) 1.9 × 10³ J
42. The root mean square velocity of one mole of a monatomic gas having molar mass M is u_rms . The relation between u_rms and the average kinetic energy E of the gas is
(a) u_rms = √(E/(3M))
(b) u_rms = √(2E/M)
(c) u_rms = √(E/(2M))
(d) u_rms = √(3E/(2M))
43. Consider the following statements regarding kinetic energy of a gas :
Statement- 1 :
At 25°C , the average kinetic energy of hydrogen gas molecules is the same as that of helium gas atoms.
Statement- 2 :
The kinetic energy of a gas depends on the temperature and does not depend on the nature of the gas.
Which one of the following is correct with respect to the 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
44. Consider the following van der Waals' constant values of two gases X and Y :
| Gas | a (kPa dm⁶ mol⁻²) | b (dm³ mol⁻¹) |
|---|---|---|
| X | 657 | 0.04 |
| Y | 363 | 0.11 |
Which one of the following is correct with respect to the van der Waals' constant values of X and Y in the table given above?
(a) X is more easily liquefied than Y
(b) Y is more easily liquefied than X
(c) Ease of liquefaction does not depend upon the van der Waals' constant a
(d) Ease of liquefaction does not depend upon the van der Waals' constant b
45. Consider the following statements regarding speed distribution of molecules :
1. The total area under the plots of (1/N)(dN_u/du) versus u is a measure of the total number of molecules in the collection.
2. The curve at any temperature is parabolic near the origin.
3. The majority of molecules have speeds which cluster around the average value ū in the distribution curve.
Which of the statements given above is/are correct?
(a) 1 and 2
(b) 1 and 3
(c) 2 and 3
(d) 3 only
46. At constant volume, the mean free path of a gas is
(a) directly proportional to temperature only
(b) inversely proportional to pressure
(c) directly proportional to both temperature and pressure
(d) independent of temperature and pressure
47. Hydrogen molecule (H₂) with molar mass 2 g mol⁻¹ effuses through a small hole at a temperature of 300 K and pressure of 5 torr. Under the same conditions, methane (CH₄) with molar mass 16 g mol⁻¹ is also allowed to effuse. The ratio of the rate of effusion of hydrogen (r_H₂) and methane (r_CH₄) is
(a) 2.828:1
(b) 1:2.828
(c) 1:8
(d) 8:1
48. The work involved in a reversible adiabatic expansion of an ideal gas from p_i and V_i to p_f and V_f is given by
w = (p_f V_f − p_i V_i)/(γ − 1)
w = (p_f V_f − p_i V_i)/(1 − γ)
w = nC_{p,m}T_i[1 − (p_f/p_i)^{c_{p,m}}]
Select the correct 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
49. Consider the following variables :
1. Dielectric constant
2. Surface tension
3. Energy
4. Enthalpy
Which one of the following regarding classification of variables is correct?
(a) 1 and 3 are intensive variables; 2 and 4 are extensive variables
(b) 1 and 2 are intensive variables; 3 and 4 are extensive variables
(c) 1 and 4 are intensive variables; 2 and 3 are extensive variables
(d) 2 and 3 are intensive variables; 1 and 4 are extensive variables
50. Consider the following statements regarding compressibility factor (Z) :
Statement- 1 :
If a system at state A is converted to state B by two methods (reversible compression and irreversible compression), then the change in internal energy of the system is the same in both the processes.
Statement- 2 :
Change in internal energy is a state function.
Which one of the following is correct with respect to the 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
51. A 0.04 mole sample of a monatomic gas at 1.00 atm pressure and 298 K expands isothermally and reversibly from an initial volume of 1.0 L to 10.0 L. It is then heated to 500 K, followed by isothermal compression to 1.00 L and finally cooled to 25 °C. The ΔU for the overall process is
(a) 228 J
(b) −228 J
(c) zero
(d) 456 J
52. Consider the following statements :
Statement- 1 :
The temperature of a perfect gas is unchanged by Joule- Thomson expansion.
Statement- 2 :
For a perfect gas, Joule- Thomson coefficient (μ) is zero.
Which one of the following is correct with respect to the 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
53. In a free expansion process
(a) the work done is zero and the heat transfer is zero
(b) the work done is zero but the heat flows into the system
(c) work is done by the system but the heat transfer is zero
(d) work is done on the system and the heat flows out of the system
54. Consider the following hypothetical reactions :
X(g) + Y(g) → XY(g); ΔH₁ = a kJ mol⁻¹
X(g) + Z(g) → XZ(g); ΔH₂ = b kJ mol⁻¹
ΔH for the reaction
Y(g) + XZ(g) → XY(g) + Z(g)
will be
(a) (a + b) kJ mol⁻¹
(b) a kJ mol⁻¹
(c) b kJ mol⁻¹
(d) (a − b) kJ mol⁻¹
55. The maximum efficiency of an engine operating between 127°C and 27°C is
(a) 78.7%
(b) 25%
(c) 21.25%
(d) 75%
56. Consider the following reaction :
H₂(g) + ½O₂(g) → H₂O(l)
The values of ΔH and ΔG are −290 kJ and −230 kJ respectively, at 300 K . What will be the value of ΔG at 320 K assuming that there is no variation of ΔH and ΔS with temperature?
(a) 0.2 kJ
(b) −532 kJ
(c) −226 kJ
(d) −49 kJ
57. Consider the following statements regarding change of enthalpy (ΔH) and change of entropy (ΔS) for a chemical reaction at any temperature T :
1. If ΔH is negative and ΔS is positive, the reaction will be spontaneous at all temperatures.
2. If ΔH is positive and ΔS is negative, the reaction will be spontaneous at low temperatures.
3. When both ΔH and ΔS are positive, the reaction will proceed spontaneously at high temperatures.
Which of the statements given above is/are correct?
(a) 1 and 2
(b) 1 and 3
(c) 2 and 3
(d) 2 only
58. Consider the following reactions :
1. H₂(g) + ½O₂(g) → H₂O(l);
ΔᵣH = −285.8 kJ mol⁻¹
2. ½N₂(g) + O₂(g) → NO₂(g);
ΔᵣH = +33.2 kJ mol⁻¹
Which one of the following is correct with respect to the above reactions?
(a) Reaction 1 is endothermic and non- spontaneous at all temperatures
(b) Reaction 2 is exothermic and spontaneous at all temperatures
(c) Reaction 2 is endothermic and non- spontaneous at all temperatures
(d) Reaction 1 is exothermic and spontaneous at all temperatures
59. The experimental results of colligative properties of solutions are often found to differ from the calculated values due to
1. association of the concerned solute
2. dissociation of the concerned solute
3. the solutions being often non-ideal
Select the correct answer using the code given below.
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
60. The vapour pressure of pure water decreases from 24 torr to 23 torr on adding x amount of a solute (molar mass 480 g mol⁻¹ ) in 150 g of water. The value of x is
(a) 114 g
(b) 128 g
(c) 167 g
(d) 1124 g
61. Consider a solution of 50 g of an enzyme dissolved in water to give 2 dm³ of solution at 27°C . The osmotic pressure of the given solution is (where molar mass of enzyme = 90000 g mol⁻¹ and R = 0.083 dm³ bar K⁻¹ mol⁻¹ )
(a) 0.49 kPa
(b) 0.69 kPa
(c) 0.89 kPa
(d) 1.09 kPa
62. Consider the following values of normal boiling point and molal boiling point elevation constant for some solvents :
| Solvent | Normal boiling point (K) | Molal boiling point elevation constant (Kb K kg mol⁻¹) |
|---|---|---|
| Water | 373.15 | 0.52 |
| Ethanol | 351.5 | 1.20 |
Which one of the following solutions would result in the greatest boiling point elevation?
(a) 0.05 M lithium chloride in water
(b) 0.05 M lithium chloride in ethanol
(c) 0.05 M magnesium chloride in water
(d) 0.05 M magnesium chloride in ethanol
63. When a non-volatile solute is dissolved in a volatile solvent, the depression in the freezing point is
(a) inversely proportional to the molality of the solution
(b) directly proportional to the molality of the solution
(c) independent of the amount of solute present in the solution
(d) directly proportional to the mole fraction of the solvent present
64. Consider the following statements regarding Henry's law :
1. The Henry's law constant depends on the nature of the gas.
2. CO₂ is more soluble than O₂
3. The Henry's law constant does not depend on the nature of the solvent.
4. The Henry's law constant depends on the temperature.
(The Henry's law constant values of CO₂ and O₂ in water at 298 K are 3.01 × 10³ kPa kg mol⁻¹ and 7.92 × 10⁴ kPa kg mol⁻¹ , respectively)
Which of the statements given above are correct?
(a) 1 and 2 only
(b) 1, 2 and 3
(c) 1, 2 and 4
(d) 3 and 4
65. The value of the Henry's law constant of O₂ in water at 298 K is 8.0 × 10⁴ kPa kg mol⁻¹ . When its partial pressure is 20 kPa , the molar concentration of O₂ in water at 25°C is
(a) 25 mmol dm⁻³
(b) 0.25 mmol dm⁻³
(c) 0.4 × 10⁻³ kg mol⁻¹
(d) 4 × 10⁻³ mol kg⁻¹
66. A conductivity cell was calibrated using 0.1 M KCl solution and the measured resistance was 100 Ω . The resistance of the same cell when filled with 0.02 M KCl solution is 500 Ω . The molar conductivity of 0.02 M KCl solution will be (the conductivity of 0.1 M KCl solution is 1.3 S m⁻¹ )
(a) 13.0 S cm² mol⁻¹
(b) 130.0 × 10⁻⁴ S cm² mol⁻¹
(c) 130.0 S cm² mol⁻¹
(d) 260.0 S cm² mol⁻¹
67. The molar conductivities at infinite dilution Λₘ^∞ for HNO₃ , CH₃COOH and NaNO₃ are 421.2 S cm² mol⁻¹ , 391.0 S cm² mol⁻¹ and 121.5 S cm² mol⁻¹ , respectively. The Λₘ^∞ for CH₃COONa will be
(a) 51.5 S cm² mol⁻¹
(b) 91.3 S cm² mol⁻¹
(c) 151.5 S cm² mol⁻¹
(d) 201.0 S cm² mol⁻¹
68. The correct order of molar conductance at infinite dilution of LiCl , NaCl and KCl is
(a) LiCl > NaCl > KCl
(b) KCl > NaCl > LiCl
(c) NaCl > KCl > LiCl
(d) KCl > LiCl > NaCl
69. Consider the following statements regarding ionic molar conductivities:
Statement- 1:
With increasing dilution, the conductivity keeps on increasing.
Statement- 2:
With increasing dilution, the degree of ionization of weak electrolytes increases, and the mobility of ions also increases.
Which one of the following is correct with respect to the 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
70. Consider the following statements regarding ionic molar conductivities :
Statement- 1 :
The Walden's rule holds good for tetramethylammonium ion and picrate ion.
Statement- 2 :
The effective radii of tetramethylammonium ion and picrate ion in the solvent are larger and very different from the crystallographic radii of the ions.
Which one of the following is correct with respect to the 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
71. Consider the following statements regarding movement of ions :
1. Ionic mobility is inversely proportional to the potential gradient.
2. Ionic mobility is directly proportional to the ionic speed.
3. Transport number of the ions is inversely proportional to the ionic speed.
4. Sum of the transport numbers of ions in a solution is equal to one.
Which of the statements given above are correct?
(a) 1 and 2 only
(b) 1, 2 and 3
(c) 3 and 4
(d) 1, 2 and 4
72. The following graph shows the variation of molar conductance with the concentration of a/an
[Image: please refer to given pdf link for image and diagram]
(a) strong acid
(b) weak acid
(c) buffer
(d) ethanol
73. Consider the following graph showing the variation of molar conductance with concentration :
[Image: please refer to given pdf link for image and diagram]
Which one of the following statements is correct with respect to the above graph?
(a) Plot 1 can be extrapolated to obtain the molar conductance at infinite dilution of weak electrolytes.
(b) Plot 1 can be extrapolated to obtain the molar conductance at infinite dilution of strong electrolytes.
(c) Plot 2 can be extrapolated to obtain the molar conductance at infinite dilution of strong electrolytes.
(d) Both plots 1 and 2 can be extrapolated to obtain the molar conductance at infinite dilution of strong and weak electrolytes, respectively.
74. The term A√c in the Onsager equation Λ = Λ∞ − (A + BΛ∞)√c represents the
(a) decrease in molar conductivity due to the electrophoretic effect
(b) decrease in molar conductivity due to the asymmetry effect
(c) increase in molar conductivity due to the electrophoretic effect
(d) increase in molar conductivity due to the asymmetry effect
75. The conductivity of 0.001M dichloroacetic acid solution is 3.88 × 10⁻⁵ S cm⁻¹ . The molar conductivities at infinite dilution for HCl, NaCl and CHCl₂COONa (sodium dichloroacetate) are 426 S cm² mol⁻¹ , 126 S cm² mol⁻¹ and 88 S cm² mol⁻¹ , respectively. The degree of dissociation and dissociation constant of dichloroacetic acid will be respectively
(a) 0.2 and 1.1 × 10⁻⁶
(b) 0.1 and 1.1 × 10⁻⁶
(c) 0.2 and 1.1 × 10⁻⁴
(d) 0.1 and 1.1 × 10⁻⁵
76. The conductivity and molar conductance of CaF₂ at 18°C are 4 × 10⁻⁵ S cm⁻¹ and 200 S cm² mol⁻¹ , respectively. The K_sp for CaF₂ will be
(a) 4.0 × 10⁻⁸
(b) 3.2 × 10⁻¹¹
(c) 8.0 × 10⁻¹²
(d) 2.0 × 10⁻¹²
77. In the given plot of conductometric titration of CH₃COOH vs. NaOH, the area around point (1) is curved due to
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(a) neutralization of weak acid with weak base
(b) hydrolysis of the salt CH₃COONa
(c) suppression of dissociation of CH₃COOH
(d) poor conductance of CH₃COOH
78. Consider the following table showing the apparent transport numbers of Cd²⁺ ion in CdI₂ solutions of different molalities :
| m/mol kg⁻¹ | t₊ |
|---|---|
| 0.05 | 0.40 |
| 0.1 | 0.36 |
| 1.0 | 0.30 |
| 2.5 | 0.10 |
| 4.0 | −0.06 |
| 5.0 | −0.12 |
| 8.0 | −0.40 |
| 10.0 | −0.60 |
Which one of the following interpretations is correct with respect to the table given above?
(a) In dilute solutions, Cd²⁺ ion migrates towards the anode and I⁻ migrates towards the cathode and vice versa in concentrated solutions.
(b) In dilute solutions, Cd²⁺ ion migrates towards the cathode and I⁻ migrates towards the anode and vice versa in concentrated solutions.
(c) In dilute solutions, Cd²⁺ ion migrates towards the cathode and I⁻ migrates towards the anode and in concentrated solutions, Cd²⁺ ion migrates towards the cathode and CdI₄²⁻ migrates towards the anode.
(d) In dilute solutions, Cd²⁺ ion migrates towards the anode and I⁻ migrates towards the cathode and in concentrated solutions, Cd²⁺ ion migrates towards the anode and CdI₄²⁻ migrates towards the cathode.
79. The transport number of ions in a 1.0 M solution of AgNO₃ was determined using a 0.3 M solution of Cd(NO₃)₂ in the moving boundary method. When a current of 15 mA was passed for 30 min , the boundary swept through a volume of 0.1 cm³ . The transport number of Ag⁺ is (Faraday's constant = 96500 C mol⁻¹ )
(a) 0.36
(b) 0.64
(c) 0.71
(d) 0.83
80. Which of the following electrolytes should be given to a chemist to be used as an indicator electrolyte in the determination of the transport number of Ag⁺ in AgNO₃ solution using the moving boundary method?
(a) Cd(NO₃)₂
(b) LiNO₃ only
(c) CdCl₂ only
(d) Both LiNO₃ and CdCl₂
81. Consider the following statements regarding structures of naphthalene and biphenylene :
1. The C1-C2 bond order is more than C2-C3 bond in naphthalene.
2. The C2-C3 bond order is more than C1-C2 bond in naphthalene.
3. The C1-C2 bond order is more than C2-C3 bond in biphenylene.
4. The C2-C3 bond order is more than C1-C2 bond in biphenylene.
Which of the statements given above are correct?
(a) 1 and 3
(b) 1 and 4
(c) 2 and 3
(d) 2 and 4
82. The correct order of increasing acid strength of the given carboxylic acids is
(a) 4-acetylbenzoic acid < 4-cyano-benzoic acid < 4-hydroxybenzoic acid < benzene-1,4-dicarboxylic acid
(b) 4-hydroxybenzoic acid < 4-acetyl-benzoic acid < 4-cyanobenzoic acid < benzene-1,4-dicarboxylic acid
(c) 4-hydroxybenzoic acid < benzene-1,4-dicarboxylic acid < 4-acetyl-benzoic acid < 4-cyanobenzoic acid
(d) 4-cyanobenzoic acid < 4-acetyl-benzoic acid < benzene-1,4-dicarboxylic acid < 4-hydroxy-benzoic acid
83. The major products [X] and [Y] formed in the following reactions are
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84. The correct decreasing order of reactivity towards ionization under acidic conditions of the following compounds is
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85. The products of the following reactions are
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86. Match the pair of compounds from Column- I with their stereochemical relationship with each other from Column- II and select the correct answer using the code given below the Columns :
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Column- I
Column- II
(A) M and N 1. Identical
(B) M and O 2. Diastereomers
(C) M and P 3. Enantiomers
(D) N and P
Code :
(a) A B C D 2 3 2 1
(b) A B C D 3 3 1 2
(c) A B C D 1 3 1 2
(d) A B C D 3 1 2 1
88. The structure which is consistent with (R,Z) -3,6-dimethyloct-3-ene as its IUPAC name is
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89. Cholic acid, a major constituent of bile, has the structure as shown below. What are the positions of labeled I, II and III hydroxyl groups, respectively, in their chair conformations?
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(a) Equatorial, equatorial and axial
(b) Equatorial, equatorial and
(c) Equatorial, axial and axial
(d) Axial, axial and axial
90. In which one of the following compounds, the anti-conformer is more stable than gauche conformer?
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91. The increasing order of S_N1 solvolysis reactivity in ethanol of the following substrates is
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92. The number of S_N2 processes involved in the mechanism of the following reaction is
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93. The major products [X] and [Y] formed in the following reactions are
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94. The major products [X] and [Y] formed in the following reactions are
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95. The relative S_N2 reactivity order of the following substrates is
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96. Which of the following statements are correct about the following reactions?
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1. Addition is favoured at low temperature whereas elimination is favoured at high temperature.
2. Addition is favoured at high temperature whereas elimination is favoured at low temperature.
3. At high temperature, ΔG is positive for addition reaction whereas ΔG is negative for elimination reaction.
4. At high temperature, ΔG is negative for addition reaction whereas ΔG is positive for elimination reaction.
Select the correct answer using the code given below.
a 1 and 3 b 1 and 4 c 2 and 3 d 2 and 4
97. The major products formed in E2 and S_N2 reactions of the substrate [X] with sodium methoxide, respectively, are
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a (Z)- 3- methylhex- 3- ene and (3R,4R) - 3- methoxy- 4- methylhexane
b (Z)- 3- methylhex- 3- ene and (3R,4S) - 3- methoxy- 4- methylhexane
c (E)- 3- methylhex- 3- ene and (3R,4S) - 3- methoxy- 4- methylhexane
d (E)- 3- methylhex- 3- ene and (3R,4R) - 3- methoxy- 4- methylhexane
98. In which one of the following elimination reactions, deuterium is not retained in the alkene formed as the major product?
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99. Which one of the following statements is correct regarding the given reaction?
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(a) The major product formed is I and is called Zaitsev product.
(b) The major product formed is I and is called Hofmann product.
(c) The major product formed is II and is called Zaitsev product.
(d) The major product formed is II and is called Hofmann product.
100. Which of the following substrates do not form trimethylamine as one of the products in its Hofmann exhaustive methylation method?
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(a) I, II and III
(b) I and II only
(c) III, IV and V
(d) IV and V only
101. Which of the compounds in Pair A and Pair B are more reactive towards elimination reaction using NaOH/EtOH?
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(a) Pair A : I is more reactive than II Pair B : III is more reactive than IV
(b) Pair A : I is more reactive than II Pair B : IV is more reactive than III
(c) Pair A : II is more reactive than I Pair B : III is more reactive than IV
(d) Pair A : II is more reactive than I Pair B : IV is more reactive than III
102. The major products [X] and [Y] formed in the following reactions are
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103. Match the reactions from Column-I with the major products formed from Column-II and select the correct answer using the code given below the Columns :
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Code :
(a) A B C 2 4 1
(b) A B C 4 3 2
(c) A B C 3 1 2
(d) A B C 3 4 1
104. Consider the following statements :
Statement- 1 :
The peroxide effect is observed for the addition of HBr to alkene but not for the addition of HCl or HI.
Statement- 2 :
Either of the two propagation steps for the addition of HCl or HI to alkene is endothermic in nature.
Which one of the following is correct with respect to the above statements?
(a) Both Statement-1 and Statement-2 are correct and Statement-2 is the correct explanation of Statement-1
(b) Both Statement-1 and Statement-2 are correct and Statement-2 is not the correct explanation of Statement-1
(c) Statement-1 is correct but Statement-2 is incorrect
(d) Statement-1 is incorrect but Statement-2 is correct
105. The reagents [X] and [Y] required to carry out the following transformations are
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(a) [X] = m -CPBA and [Y] = CH₃CO₃H
(b) [X] = CH₃CO₃H and [Y] = m -CPBA
(c) [X] = H₂O₂ /NaOH and [Y] = CH₃CO₃H
(d) [X] = CH₃CO₃H and [Y] = H₂O₂ /NaOH
106. Which one of the following statements is not correct regarding the following reaction?Dibenzalacetone + 1 mol Diethylmalonate
Dibenzalacetone + 1 mol Diethylmalonate
NaOEt Monocyclic product
(a) The product is formed by two successive Michael additions.
(b) The product is formed by Michael addition followed by intra-aldol condensation.
(c) Monocyclic product does not give the test of unsaturation with bromine.
(d) The double bond equivalence of monocyclic product is twelve.
107. Classify the following substituted styrenes with respect to their preferred mode of addition polymerization and select the correct answer accordingly :
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(a) I and IV undergo anionic polymerization while II and III undergo cationic polymerization
(b) III and IV undergo cationic polymerization while I and II undergo anionic polymerization
(c) I, III and IV undergo cationic polymerization while II undergoes anionic polymerization
(d) I and IV undergo cationic polymerization while II and III undergo anionic polymerization
108. Match the reactions from Column-I with the stereochemical outcome of the products described in Column-II and select the correct answer using the code given below the Columns :
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Code :
(a) A B C D 2 1 4 3
(b) A B C D 2 4 1 3
(c) A B C D 3 2 4 1
(d) A B C D
109. Which one of the following statements is correct for the indicated reaction? Major product
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(a) The major product formed is I and the reaction proceeds through addition-elimination pathway.
(b) The major product formed is II and the reaction proceeds through addition-elimination pathway.
(c) The major product formed is I and the reaction proceeds through elimination-addition pathway.
(d) The major product formed is II and the reaction proceeds through elimination-addition pathway.
110. The major product formed in the following reaction is
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111. The intermediate [X] and the major product [Y] formed in the following reaction are
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112. The major product formed in the following reaction is
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113. The correct sequence of reactions to accomplish the multi-step synthesis of 1-isobutyl-2-methylbenzene from benzene is
Benzene ⟶ 1-Isobutyl-2-methylbenzene
(a) [1] (CH₃)₂CHCOCl / AlCl₃ ; [2] HCl, Zn(Hg)/heat; [3] dilute H₂SO₄ ; [4] CH₃Cl, AlCl₃ ; [5] fuming H₂SO₄
(b) [1] CH₃Cl, AlCl₃ ; [2] dilute H₂SO₄ ; [3] (CH₃)₂CHCOCl / AlCl₃ ; [4] HCl, Zn(Hg)/heat; [5] fuming H₂SO₄
(c) [1] (CH₃)₂CHCl / AlCl₃ ; [2] fuming H₂SO₄ ; [3] CH₃Cl, AlCl₃ ; [4] dilute H₂SO₄
(d) [1] (CH₃)₂CHCOCl / AlCl₃ ; [2] HCl, Zn(Hg)/heat; [3] fuming H₂SO₄ ; [4] CH₃Cl, AlCl₃ ; [5] dilute H₂SO₄
114. The major products [X] and [Y] formed in the following reactions are
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115. The major product formed in the following reaction is
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116. The major products [X] and [Y] formed in the following reactions are
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117. The reasonable carbocation intermediates which are likely to form in the reaction mechanism of the following transformation are
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(a) I, III and IV
(b) III, IV and V
(c) I, II and IV
(d) II, III and V
118. Which substrate in each pair is expected to be faster in the indicated reaction?
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(a) I is more reactive than II whereas III is more reactive than IV
(b) I is more reactive than II whereas IV is more reactive than III
(c) II is more reactive than I whereas III is more reactive than IV
(d) II is more reactive than I whereas IV is more reactive than III
119. The relative rate of solvolysis in aqueous acetone of the following tertiary p-nitrobenzate esters is
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(a) I < II < III < IV
(b) I < IV < II < III
(c) IV < I < III < II
(d) II < I < IV < III
120. Arrange the following three nitrogen mustards in decreasing order of reactivity towards their possible use as alkylating agents for clinical purpose :
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(a) I > III > II
(b) II > I > III
(c) III > I > II
(d) II > III > I
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