NIOS On-Demand Exam 2025: Download Solved Chemistry Question Paper PDF for Guaranteed Success

313_TUS_Chemistry_Set-A_29-04-2024

Exam Questions

Section A (1–16 MCQs, 1 mark each)

  1. (B) CO₂
  2. (B) Osmotic pressure
  3. (D) Volume
  4. (C) NH₃
  5. (D) 104.5°
  6. (B) Oxidizing properties
  7. (B) Prominent oxidation state
  8. (B) Electromeric effect
  9. (C) Both alkenes and alkynes
  10. (C) Intermolecular dipole-dipole interaction
  11. (B) Salicylaldehyde
  12. (C) Gem-dialkoxy compounds
  13. (B) Aniline
  14. (D) Globular proteins
  15. (D) Thermoplastic
  16. (A) Soap

Section B (17–43)

17. Fill in the blanks (2 marks):

  • Molar mass of NaCl.
  • C-12 isotope.
  • 1 mm = 0.001 m.
  • Integral multiple.

18. VSEPR Theory (2 marks):

  • Arrange to minimize repulsion.
  • Bond angles link to repulsion.
  • Trigonal bipyramidal for five pairs.
  • Lone pairs are unbonded electrons.

19. True (T) or False (F) (2 marks):

  • T
  • T
  • T
  • T

20. True (T) or False (F):

  • F
  • T
  • F
  • T

21. True (T) or False (F):

  • T
  • F
  • T
  • T

22. True (T) or False (F):

  • T
  • T
  • T
  • F

23. True (T) or False (F):

  • T
  • F
  • T
  • T

24. Coordination Compounds (2 marks):

  • Ligand field strength differs (CN⁻ > F⁻).
  • Use AgNO₃ to differentiate.
  • Example: EDTA.
  • Bidentate ligand: en.

25. Ethers (2 marks):

  • Geometry: Bent.
  • React with HCl to form oxonium ions.
  • IUPAC: Methoxypropane.
  • Williamson’s synthesis: Alkyl halide + Alkoxide.

26. Nitro Compounds (2 marks):

  • IUPAC: 2-Nitro-2-methylpentane.
  • Propane + HNO₃ → Nitropropane.
  • Nitrobenzene in alkaline medium gives aniline.
  • Higher boiling points due to polarity.

27. Hormones and Vitamins (2 marks):

  • Estrogen: Reproductive processes.
  • Diabetes, pancreas.
  • B₂: Cracked lips; B₉: Anemia.
  • Fat-soluble: A and D.

28. Polymers (2 marks):

  • Monomers: Terephthalic acid, ethylene glycol.
  • Buna-S is a copolymer.
  • Condensation gives by-products.
  • Classified as linear, branched, or cross-linked.

29. Calculations (2 marks):

  • Na₃PO₄ mass: 39.15 g.
  • Empirical formula: CO₂.

30. d-Orbitals (2 marks):

Shapes: dᶻ², dₓ²₋y², dₓy, dₓz, dᵧz.

31. Bonding (2 marks):

  • Coordinate bond: Shared electron pair (e.g., NH₃ → BF₃).
  • Bond angles:
    • NH₃ = 107°
    • CH₄ = 109.5°

32. Exothermic Reactions (2 marks):

Definition: Release heat. Example: Combustion of CH₄.

33. Ionic Product (2 marks):

Ionic product of water: [H⁺][OH⁻] = 10⁻¹⁴.

34. Electrolysis (2 marks):

CuSO₄ electrolysis with Pt electrodes: Cu²⁺ → Cu (cathode); O₂ at anode.

35. Xenon Oxofluorides (2 marks):

Xe reacts with F₂ under heat/pressure.

36. Dichromate Formation (2 marks):

Na₂CrO₄ + H⁺ → Na₂Cr₂O₇ + H₂O.

37. Saytzeff’s Rule (2 marks):

Major product: More substituted alkene (e.g., 2-butene from 2-butanol).

38. Methane Geometry (3 marks):

Shape: Tetrahedral, as per VSEPR.

39. Internal Energy (3 marks):

  • ΔU = +10 kJ.
  • ΔU = -10 kJ.

40. Coordination Chemistry (3 marks):

  • Formula: [Co(H₂O)₆]³⁺; inner orbital complex = d²sp³ hybridization.
  • Hexacyanoferrate(III): Low spin; hexafluoroferrate(III): High spin.

41. Carbonyl Compounds (3 marks):

  • Aldehydes more reactive due to less steric hindrance.
  • Most acidic: 2-Chlorobutanoic acid.
  • Tollen’s test: Silver mirror test for aldehydes.

42. Colligative Properties (5 marks):

  • Freezing point: -0.12°C.
  • CaCl₂: 0.93 g needed for osmotic pressure.

43. Periodic Trends (5 marks):

  • Covalent character: SiCl₄ > SnCl₄ > Ge

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