Where, $\Lambda^{o}$ and $\Lambda^{\infty}$ are equivalent conductances at a given concentration and at infinite dilution respectively. $\alpha=\frac{8.0}{400}=2 \times 10^{-2}$
From Ostwald's dilution law (for weak monobasic acid)
$\mathrm{K}_{\mathrm{a}}=\frac{\mathrm{C} \alpha^{2}}{(1-\alpha)}$
$=\mathrm{C} \alpha^{2} \quad(\because 1>>\alpha)$
$=\frac{1}{32}\left(2 \times 10^{-2}\right)^{2}$
$=1.25 \times 10^{-5}$
$F{e^{ + 2 }} + 2{e^ - }\, \to \,Fe\,;\,\,\,\,{E^o} = - 0.440\,V$
$F{e^{ + 3 }} + 3{e^ - }\, \to \,Fe\,;\,\,\,\,{E^o} = - 0.036\,V$
તો $F{e^{ + 3 }} + {e^ - } \to \,F{e^{ + 2 }}$ માટે પ્રમાણિત ઇલેક્ટ્રોન પોટેન્શિયલ $({E^o})$ .............. $\mathrm{V}$ છે.
[Cuનું મોલર દળ : $63 \mathrm{~g} \mathrm{~mol}^{-1}, 1 \mathrm{~F}=96487 \mathrm{C}$ આપેલ છે.]
${Cu}({s})\left|{Cu}^{2+}({aq})(0.01 {M}) \| {Ag}^{+}({aq})(0.001 {M})\right| {Ag}({s})$ કોષ માટે ,કોષનો પોટેન્શિયલ $=.....\times 10^{-2} {~V}$
[ઉપયોગ : $\frac{2.303 {RT}}{{F}}=0.059$ ]