Define the following terms:
(i) Limiting molar conductivity
(ii) Fuel cell
(i) When the concentration of an electrolyte approaches zero, then its molar conductivity is known as limiting molar conductivity.
(ii) Fuel cells are the galvanic cells in which the energy of combustion of the fuels likes hydrogen, methanol. etc is directly converted into electrical energy.
The resistance of a conductivity cell filled with 0.1 mol L-1 KCl solution is 100 . If the resistance of the same cell when filled with 0.02 mol L-1 KCl solution is 520 , 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 1.29x 10-2 -1cm-1
State Faraday's first law of electrolysis. How much charge in terms of Faraday is required for the reduction of 1 mol of Cu2+ to Cu.
Calculate emf of the following cell at 298 K: Mg(s) | Mg2+(0.1 M) || Cu2+ (0.01) | Cu(s)
[Given E0 cell = +2.71 V, 1 F = 96500 C mol-1]
Account for the following:
(i) Mn2+ is more stable than Fe2+ towards oxidation to +3 state.
(ii) The enthalpy of atomization is lowest for Zn in 3d series of the transition elements.
(iii) Actinoid elements show a wide range of oxidation states.
(i) Name the elements of 3d transition series that show a maximum number of oxidation states. Why does this happen?
(ii) Which transition metal of 3d series has positive E0 (M2+/M) value and why?
(iii) Out of Cr3+ and Mn3+, which is a stronger oxidising agent and why?
(iv) Name a member of the lanthanoid series that is well-known to exhibit +2 oxidation state.
(v) Complete the following equation: MnO4- + 8H+ + 5e- -->