When 0.1 mole of MnO^2-₄ is oxidised, the quantity of electricity required to completely oxidise MnO^2-₄ to MnO^-₄ is 

1. 96500 C

2. 2*96500 C 

3. 9650 C

4. 96.50 C

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

The standard reduction potential for Fe²⁺|Fe and Sn²⁺|Sn electrodes are -0.44 V and -0.14 V respectively. For the cell reaction,

Fe²⁺ + Sn  →  Fe + Sn²⁺, the standard Emf is - 

1. +0.30 V

2. 0.58 V

3. +0.58 V

4. -0.30 V

On electrolysing a solution of dilute H₂SO₄ between platinum electrodes, the gas evolved at the anode and cathode are respectively:

1. SO₂ and O₂

2. SO₃ and H₂

3. O₂ and H₂

4. H₂ and O₂

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

In electrolysis of NaCl when Pt electrode is taken then H₂ is liberated at cathode while with Hg cathode it forms sodium amalgam because :

1. Hg is more inert than Pt

2. More voltage is required to reduce H⁺ at Hg than at Pt

3. Na is dissolved in Hg while it does not dissolve in Pt

4. Concentration of H⁺ ions is larger when Pt electrode is taken.

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

If mercury is used as cathode in the electrolysis of aqueous NaCl solution, the ions discharged at cathode are:

1. H⁺

2. Na⁺

3. OH^-

4. Cl^-

A gas X at 1 atm is bubbled through a solution containing a mixture of 1MY^- and 1MZ^- at 25$°$C. If the reduction potential of Z > Y > X, then:

1. Y will oxidise X and not Z

2. Y will oxidise Z and not X

3. Y will oxidise both X and Z

4. Y will reduce both X and Z

The solution of CuSO₄ in which copper rod is immersed is diluted to 10 times, the reduction electrode potential:

1. increases by 0.030 V

2. decreases by 0.030 V

3. increases by 0.059 V

4. decreases by 0.059 V