Mole Concept & Stoichiometry · JEE Main previous year questions

2005 4 questions

1. Q1512005 · 28 Apr 2005 · Shift 1

   Two solutions of a substance (non electrolyte) are mixed in the following manner. 480 ml of 1.5 M first solution + 520 ml of 1.2 M second solution. What is the molarity of the final mixture?

   1. A.2.70 M
   2. B.1.344 M
   3. C.1.50 M
   4. D.1.20 M
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   Answer: B

2. Q1522005 · 28 Apr 2005 · Shift 1

   If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of the substance will

   1. A.be a function of the molecular mass of the substance
   2. B.remain unchanged
   3. C.increase two fold
   4. D.decrease twice
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   Answer: B

3. Q1602005 · 28 Apr 2005 · Shift 1

   If the bond dissociation energies of $\mathrm{XY}$, ${\mathrm{X}}_2$ and ${\mathrm{Y}}_2$ (all diatomic molecules) are in the ratio of $1:1:0.5$ and $\Delta H_f$ for the formation of $\mathrm{XY}$ is $-200\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$. The bond dissociation energy of ${\mathrm{X}}_2$ will be :

   1. A.$100\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$
   2. B.$200\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$
   3. C.$300\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$
   4. D.$800\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$
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   Answer: D

4. Q2142005 · 28 Apr 2005 · Shift 1

   An ionic compound has a unit cell consisting of A ions at the corners of a cube and B ions on the centres of the faces of the cube. The empirical formula for this compound would be :

   1. A.$\mathrm{AB}$
   2. B.${\mathrm{A}}_2\mathrm{B}$
   3. C.$\mathrm{A}{\mathrm{B}}_3$
   4. D.${\mathrm{A}}_3\mathrm{B}$
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   Answer: C