A silver cup is plated with silver by passing 965 coulomb of electricity. The amount of Ag deposited is:

(1) 1.08 g

(2) 1.0002 g

(3) 9.89 g

(4) 107.89 g

 

At 25°C, molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 Ω^-1 cm² mol^-1 and at infinite dilution, its molar conductance is 238 Ω^-1 cm² mol^-1. The degree of ionization of ammonium hydroxide at the same concentration and temperature is

1. 2.080 %

2. 20.800 %

3. 4.008 %

4. 40.800 %

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

(1) forms a soluble complex with AgNO₃

(2) is oxidised to Cu²⁺

(3) is reduced to Cu^2-

(4) splits up into atoic form and dissolves

The specific conductance of a 0.1 M KCl solution at 23$°\mathrm{C}$ is 0.012 ${\mathrm{\Omega }}^{-1}{\mathrm{cm}}^{-1}$.
The resistance of the cell containing the solution at the same temperature
was found to be 55 $\mathrm{\Omega }$. The cell constant will be:

1. 0.142 cm^-1
2. 0.66 cm^-1
3. 0.918 cm^-1
4. 1.12 cm^-1

Without losing its 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

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 1.8g 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