(Important Questions - 2 Marks)
Q. Noble gases are inert. Explain.
A: Due to stable ns2 np6 (Octet) configuration (He = 1s2), they have high ionisation enthalpy and positive electron gain enthalpy they are inert. As they neither lose, gain nor share the electrons, they are inert.
Q. Give 2 uses of Neon.
A: → Neon bulbs are used in botanical gardens.
→ Ne is used in fluorescent bulbs for advertisement display purposes.
Q. Write any 2 uses of Argon.
A: →Ar is used for filling electric bulbs (to increase life of the bulb).
→Ar is used in arc welding of metals or alloys to provide inert atmosphere.
Q. Helium is heavier than H2. Yet Helium is used instead of H2 in filling baloons
for meteorological observations. Why?
A: H2 is lighter but highly inflammable gas. Where as Helium is non-inflammable and light gas (but heavier than H2). Hence 'He' is used in meteorological baloons.
Q. Name a) Most abundant noble gas in atmosphere b) Radioactive noble gas not found in atmosphere c) Noble gas with least boiling point d) Noble gas forming large number of compounds.
A: a) Argon b) Radon C) Helium D) Xenon
Q. Noble gases have very low boiling points. Why?
A: Due to presence of weak dispersion forces between noble gas atoms, they can
be liquified at very low temperatures. Hence, they have low boiling points.
Q. Why has it been difficult to study the chemistry of Radon?
A: Radon is radioactive and having very short half-life period (3.82 days), which
makes the study of chemistry of Radon is difficult.
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