Important Questions of Electrochemistry Chemistry | Zigya

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461.

In the extraction of sodium by Down's process, cathode and anode respectively are

  • copper and nickel

  • copper and chromium

  • nickel and chromium

  • iron and graphite


462.

The standard reduction potentials of Zn2+| Zn, Cu2+| Cu and Ag+| Ag are respectively -0.76, 0.34 and 0.8 V. The following cells were constructed :

(1) Zn | Zn2+ || Cu2+ | Cu

(2) Zn | Zn2+ || Ag+ | Ag

(3) Cu | Cu2+ || Ag+ |Ag

What is the correct order of Ecell° of these cells?

  • 2 > 3 > 1

  • 2 > 1 > 3

  • 1 > 2 > 3

  • 3 > 1 > 2


463.

What is the quantity of electricity (in Coulombs) required to deposit all the silver from 250 mL of 1 M AgNO3 solution?

  • 2412.5

  • 24125

  • 4825.0

  • 48250


464.

Which of the following is not correct?

  • Aqueous solution of NaCl is an electrolyte

  • The units of electrochemical equivalent are g-Coulomb

  • It the Nernst equation, n represents the number of electrons transferred in the electrode reaction.

  • Standard reduction potential of hydrogen electrode is zero volt


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465.

What is the time (in sec) required for depositing all the silver present in 125 mL of 1 M AgNO3 solution by passing a current of 241.25 A? (1F = 96500 coulombs)

  • 10

  • 50

  • 1000

  • 100


466.

Electrolysis of X gives Y at anode. Vacuum distillation of Y gives H2O. The number of peroxy (O-O) bonds present in X and Y respectively are :

  • 1, 1

  • 1, 2

  • zero, 1

  • zero, zero


467.

Assertion (A) : A current of 96.5 A is passed into aqueous AgNO3 solution for 100 s. The weight of silver deposited is 10.8 g (At. wt. of Ag = 108)

Reason (R) : The mass of a substance deposited during the electrolysis of an electrolyte is inversely proportional to the quantity of electricity passing through the electrolyte.

The correct answer is :

  • Both (A) and (R) are true and (R) is the correct explanation of (A).

  • Both (A) and (R) are true but (R) is not the correct explanation of (A).

  • (A) is true but (R) is false.

  • (A) is false but (R) is true.


468.

When same quantity of electricity is passed through aqueous AgNO3 and H2SO4 solutions connected in series, 5.04 × 10-2 g of H2 is liberated. What is the mass of silver (in grams) deposited ? (Eq. wts. of hydrogen = 1.008, silver = 108)

  • 54

  • 0.54

  • 5.4

  • 10.8


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469.

When electric current is passed through acidified waterfor 1930 s, 1120 mL of H2 gas is collected (at STP) at the cathode. What is the current passed in amperes ?

  • 0.05

  • 0.50

  • 5.0

  • 50


470.

Calculate the emf of the cell Cu(s)|Cu2+(aq)|| Ag+ (aq)| Ag(s). Given ECu2+/Cu° = +0.34 V,  EAg+/ Ag° = 0.80 V.

  • +0.46 V

  • +1.14 V

  • +0.57V

  • -0.46 V


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