BPSC TRE Previous Question Paper Quiz
विद्यालय अध्यापक परीक्षा के पूछे गए प्रश्न
For Class (1-5), (6-8), (9-10), (11-12)
Results
#1. Which of the following will have the most negative electron gain enthalpy?
Explanation: Chlorine has the most negative electron gain enthalpy among halogens due to optimal atomic size for electron acceptance.
#2. Which of the following data is expressed in scientific notation?
Explanation: Proper scientific notation requires coefficient between 1 and 10.
#3. N atom has 3 unpaired electrons because of
Explanation: Hund’s rule states electrons occupy degenerate orbitals singly before pairing up.
#4. Which molecule contains both ionic and covalent bonds?
Explanation: NH₄Cl has covalent bonds in NH₄⁺ and ionic bond between NH₄⁺ and Cl⁻.
#5. The effective nuclear charge for Na (11) is
Explanation: Effective nuclear charge = atomic number – inner electrons = 11 – 10 = +1.
#6. Arrange the following elements in the increasing order of metallic character : Si, Be, Mg, Na
Explanation: Metallic character increases down the group and decreases across period.
#7. Using s, p, d, f notations, find the orbital with quantum numbers n = 2, l = 1.
Explanation: For n=2, l=1 corresponds to p orbital, so 2p.
#8. Which of the following ions has the smallest ionic radius?
Explanation: Zn²⁺ has the smallest ionic radius due to d-block contraction. All are isoelectronic (18 electrons), but Zn²⁺ has higher effective nuclear charge.
#9. Po belongs to which period and group in the periodic table?
Explanation: Polonium (Po) is in period 6, group 16 (oxygen group).
#10. A 2·5 L flask contains 0·25 mol each of sulphur dioxide and nitrogen gas at 27 °C. The partial pressure of SO₂ is
Explanation: Using PV = nRT, P = nRT/V = (0.25 × 8.314 × 300)/0.0025 = 2.49 × 10⁵ Pa.
#11. Which of the following is the correct formula for kinetic energy based on dimensional arguments?
Explanation: Dimensions of KE are ML²T⁻², which matches ½mv².
#12. The geometrical shape of PCl₅ molecules is
Explanation: PCl₅ has sp³d hybridization with 5 bond pairs.
#13. Which of the following molecules has T-shaped geometry?
Explanation: ClF₃ has 3 bond pairs and 2 lone pairs → T-shaped.
#14. CO₂ is isostructural with which of the following?
Explanation: Both CO₂ and C₂H₂ are linear molecules.
#15. Which of the following is molecular solid?
Explanation: Methane (CH₄) is a molecular solid with weak van der Waals forces.
#16. Which of the following molecules has zero dipole moment?
Explanation: CO₂ is linear and symmetrical, dipole moments cancel.
#17. How many π bonds are present in HC≡CCH=CHCH₃?
Explanation: Triple bond (2π) + double bond (1π) = 3π bonds.
#18. Repulsion is maximum in
Explanation: lp-lp > lp-bp > bp-bp in VSEPR theory.
#19. Which of the following molecules shows metamerism?
Explanation: Ethers with formula C₄H₁₀O show metamerism.
#20. When sodium and chlorine react, then the energy
Explanation: NaCl formation is exothermic with ionic bonding.
#21. The vapour pressures of water, acetone and ethanol at 293 K are 2:34 kPa, 12:36 kPa and 5:85 kPa respectively. Which of the following has the lowest boiling point?
Explanation: Higher vapor pressure means lower boiling point; acetone has highest vapor pressure.
#22. A gas can be liquefied by pressure only if its temperature is
Explanation: Liquefaction by pressure requires temperature below critical temperature.
#23. Which of the following reactions involves homogeneous equilibrium?
Explanation: All reactants and products are gases → homogeneous equilibrium.
#24. In 2NH₃ → N₂ + 3H₂, the order of the reaction is
Explanation: Decomposition of NH₃ on tungsten surface is zero order.
#25. Which of the following statements is correct?
Explanation: Both A and B are correct; K is independent of initial concentrations.
#26. Which of the following equations represents Bragg’s law?
Explanation: This is the standard Bragg’s equation for X-ray diffraction.
#27. Write the conjugate acids for the following Brönsted bases : NH²⁻, NH₃, HCOO⁻
Explanation: Correct conjugate acids are NH₃ (for NH²⁻), NH₄⁺ (for NH₃), HCOOH (for HCOO⁻).
#28. Determine the oxidation numbers of the active elements in the following compounds : KMnO₄, K₂Cr₂O₇, KClO₄
Explanation: Mn in KMnO₄ = +7, Cr in K₂Cr₂O₇ = +6, Cl in KClO₄ = +7.
#29. Which of the following is the correct equation?
Explanation: This is Gibbs free energy equation.
#30. Which of the following is not the correct statement?
Explanation: Proton (H⁺) is a Lewis acid, not base.
#31. In the evaporation of water, the entropy
Explanation: Water molecules become more disordered during evaporation.
#32. The degree of ionization of a 0·1 M bromoacetic acid solution is 0·132. The pH of the solution is
Explanation: [H⁺] = Cα = 0.1 × 0.132 = 0.0132; pH = -log(0.0132) ≈ 1.88.
#33. Which compound is insoluble in water?
Explanation: Barium sulfate is insoluble (common solubility rule).
#34. Choose the correct statement.
Explanation: All three statements A, B, and C are correct.
#35. Which indicator will be suitable for the titration of HCOOH and NaOH?
Explanation: Weak acid-strong base titration uses phenolphthalein (pH 8-10).
#36. Choose the correct statement.
Explanation: Both B and C are correct statements.
#37. The order of correct acidic strengths of halogen acids is
Explanation: Acid strength: HI > HBr > HCl > HF due to bond dissociation energy.
#38. Which of the following has the lowest boiling point?
Explanation: H₂O has H-bonding (highest bp), H₂Se > H₂S due to larger size.
#39. In ClF₃, the nature of hybridization is
Explanation: ClF₃ has 3 bond pairs + 2 lone pairs → sp³d hybridization.
#40. What will be the conjugate bases for the following Brönsted acids? HF, H₂SO₄, HCO₃⁻
Explanation: Remove one proton from each acid to get conjugate base.
#41. Cr has electronic configuration
Explanation: Chromium shows exceptional configuration due to extra stability of half-filled d orbitals.
#42. The concentration of ore is carried out by which of the following methods?
Explanation: Both magnetic separation and froth flotation are ore concentration methods; roasting is a chemical process.
#43. Which of the following methods is used for the purification of zirconium?
Explanation: Zirconium is purified by Van Arkel method (iodide process).
#44. The highest oxidation state of any transition metal is
Explanation: Osmium and ruthenium show +8 oxidation state (e.g., OsO₄, RuO₄).
#45. Cell reaction will be spontaneous if
Explanation: Spontaneity requires ΔG < 0 (negative).
#46. Which of the following is the electron-precise hydride?
Explanation: CH₄ has exact number of electrons for covalent bonds (8 electrons around C).
#47. The atomic number of Cu is 29. Its EAN in [Cu(NH₃)₄]²⁺ is
Explanation: EAN = Atomic number – oxidation state + 2 × coordination number = 29 – 2 + (2×4) = 35.
#48. Which of the following alkali metals forms superoxide?
Explanation: Both K and Rb form superoxides (KO₂, RbO₂).
#49. Which of the following alkaline earth metals imparts colour to the flame?
Explanation: Both Ca (brick red) and Sr (crimson red) impart color to flame.
#50. The IUPAC name of K₃[Fe(CN)₆] is
Explanation: This is the systematic IUPAC name; note options A and C appear identical in text.
#51. Setting of cement gets slower by adding
Explanation: Gypsum (CaSO₄·2H₂O) retards setting of cement.
#52. Which complex has square planar structure?
Explanation: [Ni(CN)₄]²⁻ is square planar due to dsp² hybridization.
#53. Which of the following compounds is used as a purgative in medicine?
Explanation: MgSO₄ (Epsom salt) is used as a laxative/purgative.
#54. The chemical formula of sodium nitroprusside is
Explanation: Sodium nitroprusside is Na₂[Fe(CN)₅NO]·2H₂O.
#55. Which of the following is known as ‘inorganic benzene’?
Explanation: B₃N₃H₆ has structure and properties similar to benzene.
#56. Homolytic fission of the bond will form
Explanation: Homolytic cleavage gives free radicals with unpaired electrons.
#57. Which of the following boron compounds is used as a reducing agent in organic synthesis?
Explanation: Lithium borohydride is used as reducing agent for carbonyl compounds.
#58. Select the electrophilic reagent out of the following.
Explanation: Both Br⁺ (electrophile) and AlCl₃ (Lewis acid/electrophile) are electrophilic.
#59. Which of the following carbides is known as carborundum?
Explanation: SiC is known as carborundum, used as abrasive.
#60. The rotation of plane-polarized light is measured by
Explanation: Polarimeter measures optical rotation.
#61. Pure nitrogen can be obtained by which of the following reactions?
Explanation: All three reactions produce pure nitrogen gas.
#62. The alkane obtained by the electrolysis of potassium acetate is
Explanation: Kolbe electrolysis of potassium acetate gives ethane (C₂H₆).
#63. Which of the following oxides of nitrogen is used as an anaesthetic?
Explanation: Nitrous oxide (N₂O) is “laughing gas” used as anaesthetic.
#64. The hydrocarbon formed by the action of sodium on ethyl iodide is
Explanation: Wurtz reaction: 2C₂H₅I + 2Na → C₄H₁₀ + 2NaI.
#65. In which C—C bond of CH₃CH₂CH₂Br, the inductive effect is expected to be the least?
Explanation: Inductive effect decreases with distance from Br; C₂—C₃ farthest.
#66. When acetylene is passed through dilute H₂SO₄ in the presence of HgSO₄, the compound obtained is
Explanation: Hydration of acetylene gives acetaldehyde (Kucherov reaction).
#67. Identify the following transformation according to the reaction type : H₂C=CH—CH₂CH₃ → H₃CCH=CHCH₃
Explanation: Double bond migration is isomerization.
#68. Which of the following compounds shows cis-trans isomerism?
Explanation: Has two different groups on each carbon of double bond → cis-trans possible.
#69. Nitric acid is reduced to nitrogen dioxide in which of the following reactions?
Explanation: Both reactions A and B produce NO₂ from HNO₃.
#70. The synthetic method developed for the manufacture of petrol is
Explanation: Both Fischer-Tropsch and Bergius processes produce synthetic petrol.
#71. Natural rubber is a polymer of
Explanation: Natural rubber is cis-polyisoprene.
#72. Which of the following is non-aromatic based on Hückel’s rule?
Explanation: All are aromatic (have 4n+2 π electrons in cyclic conjugated system).
#73. Conformations can be represented by
Explanation: Both sawhorse and Newman projections show conformations.
#74. Which of the following reduces Tollens’ reagent?
Explanation: Glucose is reducing sugar that gives silver mirror with Tollens’ reagent.
#75. Which of the following pesticides is out of use?
Explanation: DDT banned in many countries due to environmental persistence.
#76. Arrange the following halides in order of increasing S_N2 reactivity : CH₃Cl, CH₃CH₂Cl, (CH₃)₂CHCl
Explanation: S_N2 reactivity decreases with increasing steric hindrance.
#77. Lassaigne’s test is not used for the detection of
Explanation: Lassaigne’s test detects N, S, halogens; phosphorus requires separate test.
#78. Which of the following is used in industry as a solvent for fats, waxes, resins and rubbers?
Explanation: Both CH₂Cl₂ and CHCl₃ are used as solvents for these materials.
#79. Which of the following isomers has a high melting point?
Explanation: Para isomer has symmetrical structure → higher melting point.
#80. Which of the following compounds is most acidic in character?
Explanation: Acetylene (ethyne) has acidic hydrogen due to sp hybridization.
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