When a copper wire is immersed in a solution of AgNO₃, the colour of the solution becomes blue because copper:

1. Forms a soluble complex with \(AgNO_3\)
2. Is oxidised to \(Cu^{2+}\)
3. Is reduced to \(Cu^{2-}\)
4. Splits up into atomic form and dissolves

The specific conductance of a 0.1 M KCl solution at 23 °C is 0.012  Ω^–1 cm^–1. The resistance of cells containing the solution at the same temperature was found to be 55 Ω. The cell constant will be:

Given below are two half-cell reactions:

Mn^₂₊ + 2e^-  → Mn;          E₀ = -1.18V

2Mn³⁺ + 2e^-  → 2Mn²⁺;  E₀ = +1.51V

The E₀ for 3Mn²⁺ → 2Mn⁺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:

$E_{\raisebox{1ex}{${\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