Electrochemistry 1 Question 38
37. The standard reduction-potential for the half-cell
$\mathrm{NO} _{3}^{-}(a q)+2 \mathrm{H}^{+}+e^{-} \longrightarrow \mathrm{NO} _{2}(g)+\mathrm{H} _{2} \mathrm{O}$ is $0.78 \mathrm{V}$
(i) Calculate the reduction-potential in $8 \mathrm{M} \mathrm{H}^{+}$.
(ii) What will be the reduction-potential of the half-cell in a neutral solution? Assume all the other species to be at unit concentration.
(1993, 2M)
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Solution:
- (i) $E=0.78-0.0592 \log \frac{1}{8^{2}}=0.887 \mathrm{V}$
(ii) $E=0.78-0.0592 \log \frac{1}{\left(10^{-7}\right)^{2}}=-0.0488 \mathrm{V}$
