$298\,K$ પર આપેલ કોષ માટે કોષ પોટેન્શિયલ $0.576\,V$ છે. દ્રાવણની $pH\dots\dots\dots$ છે.(નજીકનો પૂર્ણાંક)
(આપેલ : $E _{ Cu ^{2+} / Cu }=0.34\,V$ અને ધરી લો $\frac{2.303\,RT }{ F }=0.06\,V$ )
Cathode: \(Cu ^{2+}+2 e ^{-} \rightarrow Cu\)
\(\overline{ Cu ^{2+}+ H _{2} \rightarrow 2 H ^{+}+ Cu }\)
\(E _{\text {cell }}= E _{\text {cell }}^{0}-\frac{0.06}{2} \log \frac{\left[ H ^{+}\right]^{2}}{\left[ Cu ^{2+}\right]}\)
\(0.576=0.34-\frac{0.06}{2} \log \left\{\frac{\left[ H ^{+}\right]^{2}}{(0.01)}\right\}\)
\(+3.93-\log \left( H ^{+}\right)+\log 0.1\)
\(\Rightarrow pH =4.93 \simeq 5\)
$\lambda_{\mathrm{m}\left(\mathrm{H}_{2} \mathrm{SO}_{4}\right)}^{0}=\mathrm{x} \;\mathrm{S}\; \mathrm{cm}^{2} \mathrm{mol}^{-1}$
$\lambda_{\mathrm{m}\left(\mathrm{K}_{2} \mathrm{SO}_{4}\right)}^{0}=\mathrm{y} \;\mathrm{S\;cm}^{2} \mathrm{mol}^{-1}$
$\lambda_{\mathrm{m}(\mathrm{CH_3} \mathrm{COOK})}^{0}=\mathrm{z}\; \mathrm{S\;cm}^{2} \mathrm{mol}^{-1}$
$\mathrm{CH}_{3} \mathrm{COOH}$ માટે $\lambda_{\mathrm{m}}^{0}\left(\mathrm{in}\; \mathrm{S} \;\mathrm{cm}^{2} \mathrm{mol}^{-1}\right)$ શું હશે ?
$\mathrm{Cr}_2 \mathrm{O}_7{ }^{2-}+14 \mathrm{H}^{+}+6 \mathrm{e}^{-} \rightarrow 2 \mathrm{Cr}^{3+}+7 \mathrm{H}_2 \mathrm{O}, \mathrm{E}^{\circ}=1.33 \mathrm{~V}$
$\mathrm{Fe}^{3+}(\mathrm{aq})+3 \mathrm{e}^{-} \rightarrow \mathrm{Fe} \mathrm{E}^{\circ}=-0.04 \mathrm{~V}$
$\mathrm{Ni}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{Ni} \mathrm{E}^{\circ}=-0.25 \mathrm{~V}$
$\mathrm{Ag}^{+}(\mathrm{aq})+\mathrm{e}^{-} \rightarrow \mathrm{Ag} \mathrm{E}^{\circ}=0.80 \mathrm{~V}$
$\mathrm{Au}^{3+}(\mathrm{aq})+3 \mathrm{e}^{-} \rightarrow \mathrm{Au} \mathrm{E}^{\circ}=1.40 \mathrm{~V}$
આપેલી ઇલેક્ટ્રોકેમિસ્ટ્રી પ્રતિક્રિયાઓને લઈને, જે ધાતુ(ઓ) આકસ્મિક થશે તેનું ક્રોમિયમ ઓક્સાઇડ અમળમાં $\mathrm{Cr}_2 \mathrm{O}_7{ }^{2-}$ ના મૂળ્ય છે. . . . . .
$\left[\right.$ આપેલ : $K _{ sp }( AgBr )=4.9 \times 10^{-13}$ at $298 K$
$\lambda_{ Ag ^{+}}^0=6 \times 10^{-3} Sm ^2\,mol ^{-1}$
$\lambda_{ Br ^{-}}^0=8 \times 10^{-3} Sm ^2\,mol ^{-1}$
$\left.\lambda_{ NO _3^{-}}^0=7 \times 10^{-3} Sm ^2\,mol ^{-1}\right]$

($Cu$નું આણ્વિય દળ $63.5\, amu$)