Chemical Thermodynamics · JEE Main previous year questions

2005 3 questions

1. Q1582005 · 28 Apr 2005 · Shift 1

   Consider an endothermic reaction, $\mathrm{X}\to \mathrm{Y}$ with the activation energies ${\mathrm{E}}_{\mathrm{b}}$ and ${\mathrm{E}}_{\mathrm{f}}$ for the backward and forward reactions, respectively. In general :

   1. A.${\mathrm{E}}_{\mathrm{b}}<{\mathrm{E}}_{\mathrm{f}}$
   2. B.${\mathrm{E}}_{\mathrm{b}}>{\mathrm{E}}_{\mathrm{f}}$
   3. C.${\mathrm{E}}_{\mathrm{b}}={\mathrm{E}}_{\mathrm{f}}$
   4. D.There is no definite relation between ${\mathrm{E}}_{\mathrm{b}}$ and ${\mathrm{E}}_{\mathrm{f}}$
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   Answer: A

2. Q1632005 · 28 Apr 2005 · Shift 1

   The exothermic formation of $\mathrm{Cl}{\mathrm{F}}_3$ is represented by the equation: $$\mathrm{C}{\mathrm{l}}_2(\mathrm{g})+3{\mathrm{F}}_2(\mathrm{g})\rightleftharpoons 2Cl{\mathrm{F}}_3(\mathrm{g});\mathrm{\Delta H}=-329\mathrm{kJ}$$ Which of the following will increase the quantity of $\mathrm{Cl}{\mathrm{F}}_3$ in an equilibrium mixture of $\mathrm{C}{\mathrm{l}}_2$, ${\mathrm{F}}_2$ and $\mathrm{Cl}{\mathrm{F}}_3$?

   1. A.Increasing the temperature
   2. B.Removing $\mathrm{C}{\mathrm{l}}_2$
   3. C.Increasing the volume of the container
   4. D.Adding ${\mathrm{F}}_2$
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   Answer: D

3. Q1772005 · 28 Apr 2005 · Shift 1

   For a spontaneous reaction the $\Delta G$ , equilibrium constant $(\mathrm{K})$ and $E_{cell}^o$ will be respectively

   1. A.-ve, >1, +ve
   2. B.+ve, >1, -ve
   3. C.-ve, <1, -ve
   4. D.-ve, >1, -ve
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   Answer: A