Electrochemistry · JEE Main previous year questions

2002 5 questions

1. Q1762002 · 27 Apr 2002 · Shift 1

   Conductivity (Siemens S) is directly proportional to area of the vessel and the concentration of the solution in it and is inversely proportional to the length of the vessel, then the constant of proportionality is expressed in :

   1. A.$\mathrm{Sm}\mathrm{mo}{\mathrm{l}}^{-1}$
   2. B.$\mathrm{S}{\mathrm{m}}^2\mathrm{mo}{\mathrm{l}}^{-1}$
   3. C.${\mathrm{S}}^{-2}{\mathrm{m}}^2\mathrm{mol}$
   4. D.${\mathrm{S}}^2{\mathrm{m}}^2\mathrm{mo}{\mathrm{l}}^{-2}$
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   Answer: B

2. Q1792002 · 27 Apr 2002 · Shift 1

   Which of the following reaction is possible at anode?

   1. A.$2C{\mathrm{r}}^{3+}+7{\mathrm{H}}_2\mathrm{O}\to \mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7^{2-}+14{\mathrm{H}}^{+}$
   2. B.${\mathrm{F}}_2\to 2{\mathrm{F}}^{-}$
   3. C.$(1/2){\mathrm{O}}_2+2{\mathrm{H}}^{+}\to {\mathrm{H}}_2\mathrm{O}$
   4. D.none of these
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   Answer: A

3. Q1802002 · 27 Apr 2002 · Shift 1

   When the sample of copper with zinc impurity is to be purified by electrolysis, the appropriate electrodes are :

   1. A.cathode = pure zinc, anode = pure copper
   2. B.cathode = impure sample, anode = pure copper
   3. C.cathode = impure zinc, anode = impure sample
   4. D.cathode = pure copper, anode = impure sample
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   Answer: D

4. Q2082002 · 27 Apr 2002 · Shift 1

   For a cell given below $$\underset{-}{\mathrm{Ag}}|\mathrm{A}{\mathrm{g}}^{+}||\mathrm{C}{\mathrm{u}}^{2+}|\underset{+}{\mathrm{Cu}}$$ $\mathrm{A}{\mathrm{g}}^{+}+{\mathrm{e}}^{-}⟶\mathrm{Ag};E^{\circ }=x$ $\mathrm{C}{\mathrm{u}}^{2+}+2{\mathrm{e}}^{-}⟶\mathrm{Cu};E^{\circ }=y$ $E^{\circ }$ cell is :

   1. A.$x+2y$
   2. B.$2x+y$
   3. C.$y-x$
   4. D.$y-2x$
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   Answer: C

5. Q2172002 · 27 Apr 2002 · Shift 1

   Aluminium is extracted by the electrolysis of

   1. A.bauxite
   2. B.alumina
   3. C.alumina mixed with molten cryolite
   4. D.molten cryolite
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   Answer: C