In the cell represented by

Pb(s)|Pb²⁺(1M) || Ag⁺(1M)| Ag(s), the reducing agents is

• Pb²⁺

• Pb

• Ag

• Ag⁺

What is the SI unit of conductivity?

• Sm

• Sm^-1

• Sm²

• Sm^-2

423.

Consider the equilibrium obtained by electrically connecting zinc-amalgam Zn(Hg) and HgO electrodes in mercury cell,

Au(Hg) + HgO (s) $\rightleftharpoons$ ZnO (s) + Hg (l)

Under this equilibrium, what is the relation between the potential of the Zn(Hg) and HgO electrodes measured against the standard hydrogen electrode?

• Zn(Hg) electrode potential is equal to HgO electrode potential.

• Zn(Hg) electrode potential is more than HgO electrode potential.

• HgO electrode potential is more than Zn(Hg) electrode.

• Cell voltage at above said equilibrium is 1.35 V

The standard reduction potential for Zn²⁺ /Zn, Ni²⁺ /Ni and Fe²⁺ /Fe are respectively -0.76, -0.23 and -0.44 V. The reaction X + Y²⁺ → X²⁺ + Y will have more negative $∆$G value when X and Y are

• X = Ni; Y = Fe

• X = Ni; Y = Zn

• X = Fe; Y = Zn

• X = Zn; Y = Ni

The standard electrode potentials of Zn and Ni respectively are - 0.76 V and - 0.25 V. Then the standard emf of the spontaneous cell by coupling these under standard conditions is

• +1.01 V

• -0.51 V

• +0.51 V

• +0.25 V

How many moles of platinum will be deposited on the cathode when 0.60 F of electricity is passed through a 1.0 M solution of Pt⁴⁺?

• 0.60 mol

• 0.15 mol

• 0.30 mol

• 0.45 mol

A 250 W electric bulb of 80% efficiency emits a light of 6626 Å wavelength. The number of photons emitted per second by the lamp is (h = 6.636 x 10^-34 Js)

• 1.42 × 10¹⁷ 

• 2.18 × 10¹⁶ 

• 6.66 × 10²⁰ 

• 2.83 × 10¹⁶ 

Consider the following elecrolytic cells

(i) M (s) | M²⁺ (aq), 0.1 M || X²⁺ (aq), 0.01 M | X (s)

(ii) M (s) | M²⁺ (aq), 0.1 M || X² (aq), 0.01 M | X (s)

(iii) M (s) | M²⁺ (aq), 0.1 M || X² (aq), 0.01 M | X (s)

The cell EMF of the above cells are E₁, E₂ and E₃ respectively. Which one of the following is true?

• E₃ > E₂ > E₁

• E₁ > E₂ > E₃

• E₂ > E₃ > E₁

• E₁ > E₃ > E₂

When the total cell emf of a volatic cell is greater than zero, which of the following is true about the reaction quotient Q and free energy change $∆$G for the cell reaction?

• Q is less than one and $∆$G is greater than zero

• Q is greater than one and $∆$G is greater than zero

• Q is greater than one and $∆$G is less than zero

• Q is zero and $∆$G is greater than zero

In dry cell, what acts as a negative electrode?

• Zinc

• Graphite

• Ammonium chloride

• Manganese dioxide