A weak electrolyte having the limiting equivalent conductance of 400 S cm² g equiv^-1 at 298 K is 2% ionized in its 0.1 N solution. The resistance of this solution (in ohm) in an electrolytic cell of cell constant 0.4 cm^-1 at this temperature is

• 200

• 300

• 400

• 500

Given that the standard reduction potentials for M⁺ / M and N⁺ / N electrodes at 298 K are 0.52 V and 0.25 V respectively. Which of the following is correct in respect of the following electrochemical cell?

M | M⁺ || N⁺ | N

• The overall cell reaction is a spontaneous reaction

• The standard EMF of the cell is -0.27 V

• The standard EMF of the cell is 0.77 V

• The standard EMF of the cell is -0.77 V

The standard redox potential for the reactions, Mn²⁺ + 2e^- → Mn and Mn³⁺ + e^- → Mn²⁺ are -1.18 V and 1.51 V respectively. What is the redox potential for the reaction Mn³⁺ + 3e^- → Mn?

• 0.33 V

• 1.69 V

• - 0.28 V

• -0.85 V

The limiting molar conductivities of HCl, CH₃COONa and NaCl are respectively 425, 90 and 125 mho cm² mol^-1 at 25°C. The molar conductivity of 0.1 M CH₃COOH solution is 7.8 mho cm² mol^-1 at the same temperature. The degree of dissociation of 0.1 M acetic acid solution at the same temperature is

• 0.10

• 0.02

• 0.15

• 0.03

One Faraday of electricity is passed through molten Al₂O₃ , aqueous solution of CuSO₄ and molten NaCl taken in three different electrolytic cells connected in series. The mole ratio of Al, Cu and Na deposited at the respective cathode is

• 2: 3: 6

• 2: 3: 6

• 6 : 3 : 2

• 1 : 2: 3

An alloy of Pb-Ag weighing 1.08 g was dissolved in dilute HNO₃ and the volume made to 100 mL. A silver electrode was dipped in the solution and the emf of the cell set up Pt(s), H₂ (g)| H⁺ (1M) || Ag⁺ (aq) | Ag(s) was 0.62V. If E^°_cell = 0. 80V. What is the percentage of Ag in the alloy? [At 25°C, RT / F = 0.06]

• 50

• 25

• 2.50

• 10

The standard oxidation potentials of Zn, Cu, Ag and Ni electrodes are +0.76, 0.34, -0.80 and +0.25 V respectively. Which of the following reaction will provide maximum voltage?

• Cu + 2Ag⁺(aq) → Cu²⁺(aq) + 2Ag

• Zn + 2Ag⁺(aq) → Zn²⁺(aq) + 2Ag

• H₂ + Ni²⁺(aq) → 2H⁺(aq) + Ni

• Zn + Cu²⁺(aq) → Zn²⁺(aq) + Cu

Both Co³⁺ and Pt⁴⁺ have a coordination number of six. Which of the following pairs of complexes will show approximately the same electrical conductance for their 0.001M aqueous solutions?

• CoCl₃ · 4NH₃ and PtCl₄ . 4NH₃

• CoCl₃ · 3NH₃ and PtCl₄ · 5NH₃

• CoCl₃ · 6NH₃ and PtCl₄  · 5NH3

• CoCl₃ . 6NH₃ and PtCl₄ . 3NH₃

439.

An alloy of Pb-Ag weighing 1.08g was dissolved in dilute HNO₃ and the volume made to 100 mL. A silver electrode was dipped in the solution and the emf of the cell set up Pt(s), H₂(g)|H⁺(1M) || Ag⁺(aq)|Ag(s) was 0.62V. If E°_cell= 0. 80V what is the percentage of Ag in the alloy? [At 25°C, RT IF= 0.06].

• 50

• 1

• 10

• 25

The standard oxidation potentials of Zn, Cu, Ag and Ni electrodes are +0.76, 0.34, - 0.80 and +0.25 V respectively. Which of the following reaction will provide maximum voltage?

• Cu + 2Ag⁺(aq) → Cu⁺² (aq) +2Ag

• Zn + 2Ag⁺(aq) → Zn²⁺(aq) + 2Ag

• H₂ + Ni²⁺ (aq) → 2H⁺(aq) + Ni

• Zn + Cu²⁺(aq) → Zn²⁺(aq) + Cu