JEE Main 2013 — Electrochemistry Question with Solution
JEE Main 2013 (25 Apr Online)
Question
The Gibbs energy for the decomposition of at is as follows :
The potential difference needed for the electrolytic reduction of aluminium oxide at should be at least :
Choose an option
Show full solutionCorrect option: B
Correct answer
B
Step-by-step explanation
In the reaction
For the oxidation half-reaction
no. of electron transfered
$\begin{aligned}
& \Delta \mathrm{G}^{\circ}=-n \mathrm{FE}^{\circ} \\
& 940=3 \times 96500 \times \mathrm{E}^{\circ}
\end{aligned}$
$\begin{aligned}
\mathrm{E}^{\circ} & =\frac{940 \times 10^3 \mathrm{~J}}{3 \times 96500} \\
& =3.24 \approx 3 \mathrm{~V}
\end{aligned}$
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