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

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

106.

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

The standard electrode potentials of Ag⁺/Ag is +0.80V and Cu⁺/Cu is +0.34 V. These electrodes are connected through a salt bridge and if:

• copper electrode acts as a cathode then E° cell is +0.46 V

• silver electrode acts as anode then E^° cell is -0.34 V

• copper electrode acts as anode then E° cell is +0.46 V

• silver electrode acts as a cathode then E° cell is -0.34 V

If three Faradays of electricity is passed through the solutions of AgNO₃, CusO₄ and AuCl₃, the molar ratio of the cations deposited at the cathodes will be :

• 1 : 1 : 1

• 1 : 2 : 3

• 3 : 2 : 1

• 6 : 3 : 2

E${}_{\mathrm{Cu}}^{°}$ - 0.34 V; E${}_{\mathrm{Zn}}^{°}$ = 0.76 V. A Daniel cell contains 0.1 M ZnSO₄ solution and 0.01M CuSO₄ solution at its electrodes. EMF of the cell is:

• 1.10 V

• 1.04 V

• 1.16 V

• 1.07 V

When electric current is passed through an ionic hydride in molten state :

• hydrogen is liberated at anode

• hydrogen is liberated at cathode

• no change takes place

• hydride for migrates towards cathode