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 1.8 g 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 -1.2 V, +0.5 V and -3 V respectively. The reducing power of these metals will be : 

During an electrolysis experiment, if a 100 mA current is passed through a solution of AgNO₃ for 30 minutes, how many coulombs of electricity will be consumed?

1. 108 C

2. 18000 C

3. 180 C

4. 3000 C

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,E_cell 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 these

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 the electrode would be:

1. 0.059 V
2. 0.59 V
3. 00.118 V
4. 1.18 V