The number of moles of electrons required to deposit 1gm equivale

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 Multiple Choice QuestionsMultiple Choice Questions

381.

Which of the following statements is true for the electrochemical Daniell cell?

  • Electrons flow from copper electrode to zinc electrode.

  • Current flows from zinc electrode to copper electrode.

  • Cations move toward copper electrode.

  • Cations move toward zinc electrode.


382.

Assertion : Copper metal gets readily corroded is an acidic aqueous solution.

Reason : Free energy change for this process is positive.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


383.

Which of the following reactions is used to make a fuel cell?

  • Cd(s) + 2Ni(OH)3 → CdO(s) + 2Ni(OH)2(s) + H2O(l)

  • Pb(s) + PbO2(s) + 2H2SO4(aq) → 2PbSO4(s) + 2H2O(l)

  • 2H2(g) + O2(g) →6 2H2O(l)

  • 2Fe(s) + O2(g) + 4H+ (aq) → 2Fe2+(aq) + 2H2O(l)


384.

Time required to deposit one millimole of aluminium metal by the passage of 9.65 amperes through aqueous solution of aluminium ion is

  • 30 s

  • 10 s

  • 30,000 s

  • 10,000 s


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385.

A spoon to be electroplated with gold should be

  • cathode

  • anode

  • electrolyte

  • none of these.


386.

How many electrons are de! ivered at the cathode during electrolysis by a current of 1 A in 60 seconds?

  • 3.74 x 1020

  • 6.0 x 1023

  • 7.48 x 1021

  • 6.0 x 1020


387.

At a particular temperature, the ratio of equivalent conductance to specific conductance of a 0.01 N NaCl solution is

  • 105 cm3

  • 103 cm3

  • 10 cm3

  • 105 cm2


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388.

The number of moles of electrons required to deposit 1gm equivalent aluminium (atomic wt. = 27) from a solution of aluminium chloride will be

  • 3

  • 1

  • 4

  • 2


A.

3

Al3+ + 3e-  Al

Therefore, number of moles of electrons required to deposite 1 gm equivelent of aluminium is three.


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389.

At temperature of 298K, the emf of the following electrochemical cell,

Ag (s) | Ag+ (0.1 M)|| Zn2+ (0.1 M) | Zn (s) will be (Given, E°cell = -1.562 V)

  • -1.532 V

  • -1.503 V

  • 1.532 V

  • -3.06 V


390.

Assertion: Potassium and caesium are used in photoelectric cells.

Reason: Potassium and caesium emit electrons on exposure to light.

  • If both assertion and reason are true and reason is a correct explanation of the assertion.

  • If both the assertion and reason are true but the reason is not a correct explanation of the assertion.

  • If the assertion is true but the reason is false.

  • If both the assertion and reason are false.


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