1.In the button cells widely used in watches and other devices the following reaction takes place:
Zn(s) + Ag2O(s) + H2O(l ) ® Zn2+(aq) + 2Ag(s) + 2OH–(aq)
Determine ΔrG 0 and E0 for the reaction.
2.A solution of CuSO4 is electrolysed for 10 minutes with a current of 1.5 amperes. What is the mass of copper deposited at the cathode?
3.Resistance of a conductivity cell filled with 0.1 mol L–1 KCl solution is 100 W . If the resistance of the same cell when filled with 0.02 mol L–1 KCl solution is 520 W , calculate the conductivity and molar conductivity of 0.02 mol L–1 KCl solution. The conductivity of 0.1 mol L–1 KCl solution is 1.29 S/m.
4.If a current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons would flow through the wire?
5.The conductivity of 0.20 M solution of KCl at 298 K is 0.0248 S cm–1. Calculate its molar conductivity.
6.Calculate the potential of hydrogen electrode in contact with a solution whose pH is 10.
7.The conductivity of 0.001028 mol L–1 acetic acid is 4.95 × 10–5 S cm–1. Calculate its dissociation constant if Λ0m for acetic acid is 390.5 S cm2 mol–1.
8.The molar conductivity of 0.025 mol L–1 methanoic acid is 46.1 S cm2 mol–1. Calculate its degree of dissociation and dissociation constant. Given l0(H+) = 349.6 S cm2 mol–1 and λ0 (HCOO–) = 54.6 S cm2 mol–1.
9.Calculate the standard cell potentials of galvanic cell in which the following reactions take place: (i) 2Cr(s) + 3Cd2+(aq) ® 2Cr3+(aq) + 3Cd (ii) Fe2+(aq) + Ag+(aq) ® Fe3+(aq) + Ag(s)
Calculate the DRg0 and equilibrium constant of the reactions.
10.Conductivity of 0.00241 M acetic acid is 7.896 × 10–5 S cm–1. Calculate its molar conductivity. If Λ0m for acetic acid is 390.5 S cm2 mol–1, what is its dissociation constant?
11.Predict the products of electrolysis in each of the following:
(i) An aqueous solution of AgNO3 with platinum electrodes.
(ii) A dilute solution of H2SO4 with platinum electrodes.