591.

The Gibb's energy for the decomposition of Al₂O₃ at 500^o C is as follow
2/3 Al₂O₃ → 4/3 Al + O₂;
Δ_rG = +960 kJ mol^-1
The potential difference needed for the electrolytic reduction aluminium oxide (Al₂O₃) at 500⁰ C is at least 

• 4.5 V

• 3.0 V

• 2.5 V

• 2.5 V

Standard electrode potential of three metal X, Y and Z are -1.2 V, +0.5 V and -3.0 V respectively. The reducing power of these metals will be

• Y > X > Z

• Z> X> Y

• X > Y > Z

• X > Y > Z

If the E^o_cell for a given reaction has a negative value then which of the following gives the correct relationships for the values of ΔG^o and K_eq ?

• ΔG^o < 0; K_eq > 1

• ΔG^o < 0; K_eq < 1

• ΔG^o > 0; K_eq < 1

• ΔG^o > 0; K_eq < 1

The electrode potentials for 

Cu²⁺ (aq) + e^- → Cu⁺ (aq) and Cu⁺ (aq) + e^- →Cu (s)

are +0.15 V and +0.50V respectively. The value of  will be 

• 0.325 V 

• 0.650 V

• 0.150 V

• 0.150 V

Standard electrode potential for Sn⁴⁺ / Sn²⁺ couple is +0.15 V and that for the Cr³⁺/Cr  couple is -0.74. These two couples in their standard state are connected to make a cell. The cell potential will be

• +0.89 V

• +0.18 V

• +1.83 V

• +1.83 V

A solution contains Fe²⁺ Fe³⁺, and I^- ions. This solution was treated with iodine at 35^o C.E^o for Fe³⁺/ Fe²⁺ is +0.77 V and E^o for I₂/ 2 I^- = 0.536 V. The favourable redox reaction is 

• I₂ will be reduced to I^-

• There will be No redox reaction

• I^- will be oxidised to I₂

• I^- will be oxidised to I₂

In qualitative analysis, the metals of group I can be separted from other ions by precipitating them as chloride salts. A solution initially contains Ag⁺ and Pb²⁺ at a concentration of 0.10 M. Aqueous HCl is added to this solution until the Cl^- concentration is 0.10 M. What will be the concentration of Ag⁺ and Pb²⁺ be at equilibrium? (K_sp for AgCl = 1.8 x 10^-10, Ksp for PbCl₂  = 1.7 x 10^-5)

• [Ag⁺]  = 1.8 x 10^-7 M; [Pb²⁺] = 1.7 x 10^-6 M

• [Ag⁺]  = 1.8 x 10^-11 M; [Pb²⁺] = 8.5 x 10^-5 M

• [Ag⁺]  = 1.8 x 10^-9 M; [Pb²⁺] = 1.7 x 10^-3 M

• [Ag⁺]  = 1.8 x 10^-9 M; [Pb²⁺] = 1.7 x 10^-3 M

For the reaction of silver ions with copper metal, the standard cell potential was found to be +0.46 V at 25^o C^. The value of standard Gibbs energy, ΔG^o will be (F = 96500 C mol^-1 ) 

• -89.0 kJ

• -89.0 J

• -44.5 kJ

• -44.5 kJ

An increase in equivalent conductance of strong electrolyte with dilution is mainly due to

• the increase in ionic mobility of ions

• 100% ionisation of electrolyte at normal dilution

• the increase in both, ie, the number of ions and ionic mobility of ions

• the increase in both, ie, the number of ions and ionic mobility of ions

Which of the following expression correctly represents the equivalent conductance at infinite dilution of Al₂(SO₄)_3. Given that are the equivalent conductance at infinite dilution of the respective ions.