Important Questions of Electrochemistry Chemistry | Zigya

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131.

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


132.

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


133.

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.


134.

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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135.

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


136.

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


137.

A solution of concentration C g equiv/L has a specific resistance R. The equivalent conductance of the solution is

  • R/C

  • C/R

  • 1000/RC

  • 1000R/C


138.

For the following cell reaction,

Ag | Ag+ | AgCl | Cl | Cl2, Pt

Gf° (AgCl) = - 109 kJ/ mol

Gf° (Cl) = -129 kJ/ mol

Gf°(Ag+) = 78 kJ/ mol

E° of the cell is

  • -0.60 V

  • 0.60 V

  • 6.0 V

  • None of these


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139.

Which one of the following is most effective in causing the coagulation of an As2S3 sol?

  • KCl

  • AlCl3

  • MgSO4

  • K3Fe(CN)6


140.

At a certain temperature and at infinite dilution, the equivalent conductances of sodium benzoate, hydrochloric acid and sodium chlonde are 240, 349 and 229 ohm-1 cm2equiv-1 respectively. The equivalent conductance of benzoic acid in ohm-1 cm2equiv-1 at the same conditions is

  • 80

  • 328

  • 360

  • 408


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