Given below are the half-cell reactions,

Mn²⁺ + 2e^-  $\to \; Mn; \; \; \; \; \; \; E0\; =\; -1.18V$

$$ \to \; 2Mn2+; \; E0\; =\; +1.51V$$

$$ E0 for\; 3\; Mn2+ \to \; 2\; Mn+3 \; +$$Mn will be:

$$ $ 1.\; -2.69V;\; the\; reaction\; will\; not\; occur$$$

$$ $ 2.\; -2.69V;\; the\; reaction\; will\; occur$$$

$$ $ $ 3.\; -0.33V;\; the\; reaction\; will\; not\; occur$$$$

$$ $ $ $ 4.\; -0.33V;\; the\; reaction\; will\; occur$$$$$

E⁰ for Fe²⁺ + 2e → Fe is -0.44 volt and E⁰ for Zn²⁺ + 2e→ Zn is -0.76 volt, thus:

1. Zn is more electropositive than Fe

2. Fe is more electropositive than Zn

3. Zn is more electronegative

4. none of the above  

The voltage of the cell given below increases with: 

Cell: Sn(s) + 2Ag⁺(aq) → Sn²⁺(aq) + 2Ag(s)

1. Increase in size of the silver rod.

2. Increase in the concentration of Sn²⁺ ions.

3. Increase in the concentration of Ag⁺ ions.

4. None of the above.

A 5A current is passed through a solution of copper sulphate for 40 min. The amount of copper deposited at the cathode is 

1. 40.65g

2. 0.45g

3. 3.94g

4. 65.04g

$E_{\raisebox{1ex}{${\mathrm{Fe}}^{2+}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{Fe}$}\right.}^{\circ } = -0.441 \mathrm{V} and E_{\raisebox{1ex}{${\mathrm{Fe}}^{3+}$}\!\left/ \!\raisebox{-1ex}{${\mathrm{Fe}}^{2+}$}\right.}^{\circ } =0.771 \mathrm{V}$, the standard emf of the reaction

$\mathrm{Fe} + 2{\mathrm{Fe}}^{3+} \stackrel{ }{\to }3{\mathrm{Fe}}^{2+}$will be

1. 0.111V

2. 0.330V

3. 1.653V

4. 1.212V

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: 

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 :

1. Au

2. Al

3. Pb

4. Ag

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