1. Which of the following doesn't displace hydrogen?[IOM 2066]
(c) Helium (He) is a noble gas and doesn't react with other elements to displace hydrogen. 2. A deuteron contains[MOE]
- A neutron and a proton
- A neutron and a positron
- A neutron and two protons
- A proton and two neutrons
(a) Deuteron (²H⁺) is the nucleus of deuterium, containing 1 proton and 1 neutron. 3. Ortho and para hydrogen differ in[I.E.]
- Spin of electron
- Spin of proton
- Number of proton
- All of these
(b) Ortho-H₂ has parallel proton spins while para-H₂ has antiparallel proton spins. 4. Hydrogen, deuterium and tritium have[MOE]
- Different protons
- Different electrons
- Different neutrons
- Same no. of neutrons
(c) Isotopes differ in neutron count: ¹H (0), ²H (1), ³H (2 neutrons). 5. In preparation of vanaspati ghee, the reaction involving hydrogen is called[IOE/MOE]
- Reduction
- Dehydrogenation
- Hydrogenation
- Oxidation
(c) Hydrogenation converts vegetable oils (unsaturated) to ghee (saturated) using H₂ with Ni catalyst. - Covalent hydrides
- Metallic hydride
- Ionic hydrides
- All of the above
(d) H forms covalent (e.g., CH₄), ionic (e.g., NaH), and metallic hydrides (e.g., PdH). 7. The most reactive form of hydrogen is[I.E.]
- Atomic
- Ordinary
- Nascent
- Adsorbed
(a) Atomic hydrogen (H•) is highly reactive due to unpaired electron. 8. Ortho and para forms of hydrogen can be separated by[I.E.]
- Ion exchanger process
- Solvent extraction
- Gas chromatography
- Chromatography
(c) Low-temperature gas chromatography exploits their different boiling points (ortho: -252.8°C, para: -253.1°C). 9. Lane's process is for[K.U.]
- Preparation of H₂
- Purification of metal
- Preparation of H₂O₂
- Preparation of Na₂SO₄·10H₂O
(a) Lane's process produces H₂ by passing steam over red-hot iron (3Fe + 4H₂O → Fe₃O₄ + 4H₂). 10. Atomic hydrogen produces formaldehyde when it reacts with[IOM 2004]
- Water
- Formic acid
- Carbon monoxide
- Carbon dioxide
(c) H• + CO → HCHO (formaldehyde). 11. Hydrogen cannot be obtained by[IOM 2005]
- Zn and dil. H₂SO₄
- Zn + dil. HNO₃
- Mg + H₂SO₄
- Mg and H₂O
(b) Dilute HNO₃ is oxidizing; produces NO/NO₂ rather than H₂ with Zn. 12. Hydrogen burns in air with a[MOE]
- Yellow flame
- Green flame
- Pale blue flame
- Red flame
(c) H₂ combustion produces a pale blue, nearly invisible flame (forming H₂O). 13. Which particle is emitted by tritium?[I.E.]
- α-particle
- β-particle
- X-ray
- Neutron
(b) Tritium (³H) undergoes β-decay: ³H → ³He + e⁻ + ν̄ (half-life 12.3 years). 14. Which has equal no. of neutrons and protons?[BPKIHS 2005]
(d) ³Li₇ has 3 protons and 4 neutrons (not equal); none in options have equal n/p (¹H₁ has 0 neutrons). 15. H loses electron to form H⁺. In this aspect H behaves as[MOE 2008]
- Alkali metal
- Noble gas
- Alkaline earth metal
- Halogens
(a) Like Group 1 metals, H can lose 1e⁻ to form H⁺ (though it's not a true metal). 16. Finely divided nickel is used as a catalyst in[MOE 2050]
- Haber's process (NH₃)
- Ostwald process (HNO₃)
- Hydrogenation of oil
- Contact process (H₂SO₄)
(c) Ni catalyzes hydrogenation of unsaturated fats (e.g., vegetable oil → margarine). 17. Which is reduced by H₂?[MOE 2069]
(a) H₂ reduces CuO to Cu (CuO + H₂ → Cu + H₂O); Al₂O₃ is too stable. 18. Hydrogen differs from halogens in[Bangladesh, Embassy 2001]
- Ionization energy
- Electropositive nature
- Electronegativity
- Reaction with alkali metals
(b) H can lose e⁻ (electropositive), while halogens gain e⁻ (electronegative). 19. Which contains acidic hydrogen atom?[K.U. 2004]
- Ethylene
- Ethyne
- Ethane
- Butylene
(b) Ethyne (HC≡CH) has acidic H (pKa≈25) due to sp-hybridized C. 20. NaI is an example of[I.E. 2001]
- Ionic hydride
- Metallic hydride
- Molecular hydride
- Polymeric hydride
(c) NaI is a molecular (covalent) hydride, though technically not a hydride (contains I⁻). 21. The gas used in sterilizing water is[MOE 2066]
- Sulphur dioxide
- Ozone
- Nitric oxide
- Ammonia
(b) Ozone (O₃) kills pathogens via oxidation (stronger than chlorine). 22. Heavy water is used as[BPKIHS]
- Washing water
- Detergent
- Drinking water
- A moderator
(d) D₂O slows neutrons in nuclear reactors without absorbing them. 23. Maximum hydrogen bonds a water molecule can form is[BPKIHS]
(b) Each H₂O can donate 2 H-bonds and accept 2 (total 4, though typically 3.4 in liquid). 24. Which produces hard water?
- Saturation with CaCO₃
- Saturation with MgCO₃
- Saturation with CaSO₄
- Addition of Na₂SO₄
(c) CaSO₄ (gypsum) causes permanent hardness (insoluble in water). 25. Calgon's process uses[MOE]
- Slaked lime
- Sodium hexametaphosphate
- Sodium-aluminium silicate
- Sodium carbonate
(b) (NaPO₃)₆ sequesters Ca²⁺/Mg²⁺ ions, preventing scale formation. 26. Best method to test water presence?[MOE, IOM 1998]
- Taste
- Smell
- Litmus paper
- Anhydrous CuSO₄
(d) White CuSO₄ turns blue (CuSO₄·5H₂O) on water absorption. 27. High density of water vs ice is due to[MOE]
- Ionic bonding
- Covalent bonding
- Hydrogen bonding
- Dipole-dipole interaction
(c) H-bonding in ice creates open hexagonal structure (less dense than liquid water). 28. A hydrated salt losing water in air is called[MOE]
- Efflorescent
- Deliquescent
- Hygroscopic
- None
(a) Efflorescent salts (e.g., Na₂CO₃·10H₂O) lose water vapor to air. 29. Calgon is[MOE/IOM 2004]
- Na₂[Na₄(PO₃)₆]
- Na₄[Na₂(PO₃)₆]
- Na₂[Na₄(PO₄)₅]
- Na₄[Na₄(PO₄)₆]
(a) Sodium hexametaphosphate: (NaPO₃)₆. - Diamagnetic
- Paramagnetic
- Ferromagnetic
- Non-magnetic
(a) Water weakly repels magnetic fields (all paired electrons). 31. A dilute H₂O₂ solution can be concentrated by
- Drying over CaCl₂
- Drying over H₂SO₄
- Drying over MgSO₄
- Heating under reduced pressure
(d) Gentle vacuum evaporation avoids H₂O₂ decomposition. 32. Fenton's reagent is[BPKIHS]
- SnCl₂ + HCl
- AgNO₃ + NH₂OH
- CuSO₄ + NaOH
- FeSO₄ + H₂O₂
(d) Fe²⁺/H₂O₂ generates •OH radicals for oxidation. 33. The oxide that gives H₂O₂ with dilute acid is[BPKIHS]
(b) Na₂O₂ + H₂SO₄ → Na₂SO₄ + H₂O₂. 34. Moderator in nuclear reactor is[BPKIHS]
- Uranium-235
- Uranium-238
- Cadmium
- Heavy water
(d) D₂O slows neutrons without absorbing them (better than graphite). 35. H₂S + H₂O₂ → S + H₂O shows[MOE]
- Acidic nature of H₂O₂
- Alkaline nature of H₂O₂
- Oxidizing nature of H₂O₂
- Reducing nature of H₂O₂
(c) H₂O₂ oxidizes S²⁻ to S⁰ (oxidation state -2 → 0). 36. Volume strength of 1.5 N H₂O₂ is
(b) 1.5 N = 0.75 M → Volume strength = 11.2 × M = 8.4. 37. H₂O₂ acts as oxidizing agent with[BPKIHS]
(a) H₂O₂ oxidizes black PbS to white PbSO₄ (used in art restoration). 38. Permanent hardness is due to[BPKIHS]
- Carbonates of K/Na
- Bicarbonates of K/Na
- Sulphates of K/Na
- Chlorides of Ca/Mg
(d) CaCl₂/MgCl₂ remain soluble even after boiling (unlike bicarbonates). 39. Calgon process involves[MOE 2003]
- Ion-exchange
- Formation of soluble complex
- Scum
- Precipitation
(b) (NaPO₃)₆ forms soluble [Ca(PO₃)₆]⁴⁻ complexes. 40. Acid rain doesn't contain[MOE 2060]
- Sulphuric acid
- Acetic acid
- Nitric acid
- Carbonic acid
(b) Mainly H₂SO₄/HNO₃ from SO₂/NOx; H₂CO₃ is weak/natural; CH₃COOH is negligible. 41. Which is correct?[MOE 2050]
- Nitration in benzene is nucleophilic substitution
- HNO₃ acts as reducing agent
- CH₃OCH₃ and CH₃CH₂OH are metamers
- H₂O is a polar solvent
(d) H₂O's polarity (μ=1.85 D) enables it to dissolve ionic/polar compounds. 