Al₂O₃ is reduced by electrolysis at low potentials and high currents. If 4.0 x 10⁴ A of current is passed through molten Al₂O₃ for 6 h, what mass of aluminium is produced? (Assume 100% current efficiency, atomic mass of Al = 27g mol^-1)

1. 9.0 x 10³ g 

2.  8.1 x 10⁴ g

3.  2.4 x 10⁵ g

4.  1.3 x 10⁴ g

The standard reduction potential at 290 K for the following half reactions are,

(i) Zn²⁺ + 2e— → Zn(s);      E° = -0.762 V

(ii) Cr³⁺ + 3e → Cr(s);          E° = -0.740 V

(iii) 2H⁺ + 2e → H₂(g); ·      E° = -0.000 V

(iv) Fe³⁺ + e → Fe²⁺;         E° = +0.77V

Which is the strongest reducing agent?

(1) Zn

(2) Cr

(3) Fe²⁺

(4) H₂

The Zn acts as sacrificial or cathodic protection to prevent rusting of iron because:

(1) $E_{OP}^{\circ }$ of Zn < $E_{OP}^{\circ }$ of Fe

(2) $E_{OP}^{\circ }$ of Zn > $E_{OP}^{\circ }$ of Fe

(3) $E_{OP}^{\circ }$ of Zn = $E_{OP}^{\circ }$ of fe

(4) Zn is cheaper than iron

What mass of copper will be deposited by passing 2 Faraday of electricity through a solution of Cu(II) salt?

(1) 35.6 g

(2) 63.5 g

(3) 6.35 g

(4) 3.56 g

The same amount of electricity was passed through two cells containing molten Al₂O₃ and molten NaCl. If 1.8g of Al were liberated in one cell, the amount of Na liberated in the other cell is:

(1) 4.6 g

(2) 2.3 g

(3) 6.4 g

(4) 3.2 g

Standard Reduction electrode potential of three metals X, Y and Z are -1.2V, + 0.5V and -3V respectively. The reducing power of these metals will be 

(1) Y>X>Z

(2) Z>X>Y

(3) X>Y>Z

(4) Y>Z>X

How many columbs of electricity are consumed when 100 mA current is passed through a solution of AgNO₃ for 30 minute during an electrolysis experiment?

(1) 108

(2) 18000

(3) 180

(4) 3000

Standard reduction potentials at 25$°$C of Li⁺/Li, Ba²⁺/Ba, Na⁺/Na and Mg²⁺/Mg are -3.05, -2.90, -2.71 and -2.37 V respectively. Which one of the following is the strongest oxidising agent ?

(1) Mg²⁺

(2) Ba²⁺

(3) Na⁺

(4) Li⁺

For the cell, Ti/Ti⁺(0.001M)||Cu²⁺(0.1M)|Cu, ${\mathrm{E}}_{\mathrm{cell}}^{\mathrm{o}}$ $$at

25 $°$C is 0.83 V. E_cell can be increased :

1. By increasing [Cu²⁺]

2. By increasing [Ti⁺]

3. By decreasing [Cu²⁺]

4. None of the above.

A hydrogen gas electrode is made by dipping platinum wire in a solution of HCI of pH = 10 and by passing hydrogen gas around the platinum wire at 1 atm pressure. The oxidation potential of electrode would be

1. 0.059 V

2. 0.59 V

3. 00.118 V

4. 1.18 V