PrepBharat

1. EMF of a cell in terms of reduction potential of its left and right electrodes is
a) \[E = E_{left} - E_{right}\]
b) \[E = E_{left} + E_{right}\]
c) \[E = E_{right} - E_{left}\]
d) \[E =-\left( E_{right} + E_{left}\right)\]

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2. If \[\phi\] denotes reduction potential, then which is true?
a) \[E^{\circ}_{cell}=\phi_{right}-\phi_{left}\]
b) \[E^{\circ}_{cell}=\phi_{left}+\phi_{right}\]
c) \[E^{\circ}_{cell}=\phi_{left}-\phi_{right}\]
d) \[E^{\circ}_{cell}=-\left(\phi_{left}+\phi_{right}\right)\]

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3.What will be the emf for the given cell \[Pt\mid H_{2}\left(P_{1}\right)\mid H^{+}\left(aq\right)\mid \mid H_{2}\left(P_{2}\right)\mid Pt\]
a) \[\frac{RT}{f}log \frac{P_{1}}{P_{2}}\]
b) \[\frac{RT}{2f}log \frac{P_{1}}{P_{2}}\]
c) \[\frac{RT}{f}log \frac{P_{2}}{P_{1}}\]
d) None of these

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4. Which of the following reaction is possible at anode?
a) \[2 Cr^{3+}+7H_{2}O\rightarrow Cr_{2}O_7^{2-}+14 H^{+}\]
b) \[F_{2}\rightarrow 2F^{-}\]
c) \[\left(1/2\right)O_{2}+2H^{+}\rightarrow H_{2}O\]
d) None of these

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5. For a cell reaction involving a two-electron change, the standard e.m.f. of the cell is found to be 0.295 V at 25ºC. The equilibrium constant of the reaction at 25ºC will be
a) \[29.5 × 10^{-2}\]
b) 10
c) \[1 × 10^{10}\]
d) \[1 × 10^{-10}\]

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6. Standard reduction electrode potentials of three metals A, B & C are respectively + 0.5 V, – 3.0 V & –1.2 V. The reducing powers of these metals are
a) A > B > C
b) C > B > A
c) A > C > B
d) B > C > A

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7. When during electrolysis of a solution of \[AgNO_{3}\]   9650 coulombs of charge pass through the electroplating bath, the mass of silver deposited on the cathode will be
a) 10.8 g
b) 21.6 g
c) 108 g
d) 1.08 g

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8. For the redox reaction :
\[Zn\left(s\right)+Cu^{2+}\left(0.1M\right)\rightarrow Zn^{2+}\left(1 M\right)+Cu\left(s\right)\]
taking place in a cell, \[E^{\circ}_{CeII}\]  is 1.10 volt. \[E^{\circ}_{CeII}\]  for the cell will
be \[2.303\frac{RT}{F}=0.0591\]
a) 1.80 volt
b) 1.07 volt
c) 0.82 volt
d) 2.14 volt

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9. Several blocks of magnesium are fixed to the bottom of a ship to
a) make the ship lighter
b) prevent action of water and salt
c) prevent puncturing by under-sea rocks
d) keep away the sharks

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10. In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to
a) produce high purity water
b) create potential difference between two electrodes
c) generte heat
d) remove adsorbed oxygen from electron surfaces

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