1. XeF4 on partial hydrolysis produces
(b) XeF4 + H2O → XeOF2 + 2HF (partial hydrolysis). 2. Number of unpaired electrons in inert gas is
(a) Noble gases have completely filled valence shells (no unpaired electrons). 3. The element which has not yet been reacted with F2 is
(a) Argon does not form stable compounds with fluorine. 4. The most abundant inert gas in the atmosphere is
(c) Argon constitutes ~0.93% of Earth's atmosphere. 5. The number of lone pair of electrons present on Xe in XeF2 is
(a) XeF2 has linear shape with 3 lone pairs on Xe (sp3d hybridization). 6. Which of the following is the life saving mixture for an asthma patient?
- Mixture of helium and oxygen
- Mixture of neon and oxygen
- Mixture of xenon and nitrogen
- Mixture of argon and oxygen
(a) He-O2 mixture reduces breathing resistance (low density of He). 7. Noble gases are group of elements, which exhibit very
- High chemical activity
- Low chemical activity
- Minimum electronegativity
- Less diamagnetic properties
(b) Noble gases are chemically inert due to stable electronic configuration. 8. XeF6 on complete hydrolysis gives
(c) XeF6 + 3H2O → XeO3 + 6HF. 9. The correct order of solubility in water for He, Ne, Ar, Kr, Xe is
- He > Ne > Ar > Kr > Xe
- Ne > Ar > Kr > He > Xe
- Xe > Kr > Ar > Ne > He
- Ar > Ne > He > Kr > Xe
(c) Solubility increases with atomic size (London dispersion forces). 10. The noble gas was first time discovered by
- Cavendish
- William Ramsay
- Lockyer
- Frankland
(b) William Ramsay discovered Argon in 1894. 11. Noble gases don't occur in
- Sea water
- Ores
- Atmosphere
- Natural gas
(b) They occur freely in nature (not chemically combined in ores). 12. B.Pt. and M.Pt. of inert gases are
(d) Weak van der Waals forces result in very low boiling/melting points. 13. The most volatile of all liquids is
- Ether
- Liquid H2
- Liquid Nitrogen
- Liquid Neon
(b) Liquid helium has the lowest boiling point (4.2 K). 14. The mixture of noble gases is separated by
- Ramsay-Rayleigh's first method
- Ramsay-Rayleigh's second method
- Fischer and Ringe method
- Dewar's coconut charcoal adsorption method
(d) Dewar's method uses differential adsorption on activated charcoal at low temps. 15. Monazite is a source of
(a) Monazite sand contains trapped helium from radioactive decay. 16. The gas that surrounds a radioactive element is
(a) Alpha particles (He2+) capture electrons to form He gas. 17. When electric discharge is passed through neon at low pressure, the colour of the glow is
(a) Neon emits characteristic red-orange light in discharge tubes. 18. The noble gas mixture is cooled in a coconut bulb at 173 K. The gases that are not adsorbed are
- He and Xe
- Ne and Xe
- He and Ne
- Ar and Kr
(c) He and Ne have lowest adsorption due to small atomic size. 19. Which noble gas is most abundant in atmosphere?[BPKIHS]
(b) Argon (Ar) is ~0.93% of air by volume. 20. Sea divers use mixture of He and O2 because[BPKIHS 2006]
- It is higher than N2
- It doesn't dissolve in blood at high pressure
- It is easily available
- It is less reactive than N2
(b) He-O2 prevents nitrogen narcosis (low solubility of He in blood). 21. Which of the following gas is used in conducting tube of tube light for colouring purpose?[MOE 2052]
(a) Neon gives red-orange glow; other gases are used for different colors. 22. Which of the following is most reactive?[KU 2008]
(b) Xenon forms compounds with F2 and O2 due to lower ionization energy. 23. What is formed when xenon combines with fluorine in presence of mercury vapour?[BPKIHS/I.E]
(c) Xe + F2 → XeF2 (Hg vapor acts as catalyst). 24. The coloured discharge tube for advertisement mainly contains[MOE]
(c) Neon signs produce bright red-orange light. 25. Which gas is used to fill the electric bulbs/tubes?[MOE]
(c) Argon prevents filament oxidation and prolongs bulb life. 26. When the mineral clevite is heated, it gives off the inert gas
(a) Clevite contains uranium/thorium that emit α-particles (He2+). 27. The noble gas whose ionization enthalpy is closest to that of oxygen is
(d) Xe (1170 kJ/mol) ≈ O2 (1175 kJ/mol). 28. Which of the following is an explosive compound?
(d) Dry XeO3 is highly explosive (22× more than TNT). 29. The noble gas which forms interstitial compounds is
(d) Xe forms clathrates with water/quinol (not true chemical bonds). 30. Which radioactive element is inert gas?
(b) Radon (Rn) is the only radioactive noble gas. 31. Which of the following gases is not polarisable?
(a) He's small size prevents electron cloud distortion (low polarizability). 32. Shape of XeF4 molecule is
- Square planar
- Linear
- Pyramidal
- Tetrahedral
(a) XeF4 has sp3d2 hybridization with 2 lone pairs (square planar). 