, the standard emf of the reaction
The standard electrode potential for Sn4+/Sn2+ couple is +0.15 V and that for the Cr3+/Cr couple is -0.74 V. These two couples in their standard state are connected to make a cell. The cell potential will be:
1. +0.89 V
2. +0.18 V
3. +1.83 V
4. +1.199 V
If an iron rod is dipped in CuSO4 solution, then:
1. Blue colour of the solution turns red.
2. Brown layer is deposited on iron rod.
3. No change occurs in the colour of the solution.
4. None of the above.
Without losing it's concentration, ZnCl2 solution cannot be kept in contact with :
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?
Which graph correctly correlates Ecell as a function of concentrations for the cell (for different values of M and M') ?
The most convenient method to protect the bottom of the ship made of iron is
1. coating it with red lead oxide
2. white tin plating
3. connecting it with Mg block
4. connecting it with Pb block
When 0.1 mole of MnO2-4 is oxidised, the quantity of electricity required to completely oxidise MnO2-4 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. of Zn < of Fe
2. of Zn > of Fe
3. of Zn = of fe
4. Zn is cheaper than iron