Mole Concept & Stoichiometry · JEE Main previous year questions

2010 3 questions

1. Q612010 · 25 Apr 2010 · Shift 1

   The energy required to break one mole of $\mathrm{Cl}-\mathrm{Cl}$ bonds in $\mathrm{C}{\mathrm{l}}_2$ is $242\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$. The longest wavelength of light capable of breaking a single $\mathrm{Cl}-\mathrm{Cl}$ bond is ($\mathrm{c}=3\times 10^8\mathrm{m}{\mathrm{s}}^{-1}$ and ${\mathrm{N}}_{\mathrm{A}}=6.02\times 10^{23}\mathrm{mo}{\mathrm{l}}^{-1}$)

   1. A.$594\mathrm{nm}$
   2. B.$640\mathrm{nm}$
   3. C.$700\mathrm{nm}$
   4. D.$494\mathrm{nm}$
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   Answer: D

2. Q722010 · 25 Apr 2010 · Shift 1

   One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44 u. The alkene is

   1. A.propene
   2. B.1–butene
   3. C.2–butene
   4. D.ethene
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   Answer: C

3. Q872010 · 25 Apr 2010 · Shift 1

   If $10^{-4}\mathrm{d}{\mathrm{m}}^3$ of water is introduced into a $1.0\mathrm{d}{\mathrm{m}}^3$ flask at 300 K, how many moles of water are in the vapour phase when equilibrium is established ? (Given : Vapour pressure of ${\mathrm{H}}_2\mathrm{O}$ at 300 K is 3170 Pa ; $\mathrm{R}=8.314\mathrm{J}{\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}$)

   1. A.$5.56\times 10^{-3}\mathrm{mol}$
   2. B.$1.53\times 10^{-2}\mathrm{mol}$
   3. C.$4.46\times 10^{-2}\mathrm{mol}$
   4. D.$1.27\times 10^{-3}\mathrm{mol}$
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   Answer: D