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 E${}_{\mathrm{cell}}^{°}$ of these cells?

• 2 > 3 > 1

• 2 > 1 > 3

• 1 > 2 > 3

• 3 > 1 > 2

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

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

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

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

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.

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

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

Calculate the emf of the cell Cu(s)|Cu²⁺(aq)|| Ag⁺ (aq)| Ag(s). Given ${\mathrm{E}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}^{°} = +0.34 \mathrm{V}, {\mathrm{E}}_{{\mathrm{Ag}}^{+}/ \mathrm{Ag}}^{°} = 0.80 \mathrm{V}$.

• +0.46 V

• +1.14 V

• +0.57V

• -0.46 V