(a) Following reactions occur at cathode during the electrolysis of aqueous silver chloride solution :
`Ag+ (aq) + e^(-) to Ag (s), E° = + 0.80 V`
`H^(+) (aq) + e^(-) to 1/2H_(2)(g) ,E^(@) = 0.00 V`
On the basis of their standard reduction electrode potential (E°) values, which reaction is feasible at the cathode and why? (b) Define limiting molar conductivity. Why conductivity of an electrolyte solution decreases with the decrease in concentration ?

Explanation

(a) The reaction with a higher value of electrode potential is preferred. Hence `Ag^(+)` will be deposited in preference to `H^(+)`.
`Ag^(+) (aq) + e^(-) to Ag (s) `
(b) When the concentration of the solution approaches zero, molar conductivity is called limiting molar conductivity. Conductivity of an electrolyte solution decreases with decrease in concentration. Conductivity of a solution at any concentration is the conductance of one unit volume of the solution kept between platinum electrodes with unit area of cross section and at a distance of unit length. With dilution, the number of ions per unit volume decreases. Therefore conductivity of the solution decreases with decrease in concentration.