JEE Main 2023 — Chemistry Physical Chemistry

2023integerhard

${\mathrm{FeO}}_{4}^{2-}\overset{+2.2V}{\longrightarrow }{\mathrm{Fe}}^{3+}\overset{+0.70V}{\longrightarrow }{\mathrm{Fe}}^{2+}\overset{-0.45V}{\longrightarrow }{\mathrm{Fe}}^{0}$

${E}_{{\mathrm{FeO}}_{4}^{2-}/{\mathrm{Fe}}^{2+}}^{\theta }$ is $x\times {10}^{-3}V$ . The value of $x$ is _______

Official previous-year question

Held on 10 Apr 2023 · Verified 6 Jul 2026.

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Solution

The relation between $\Delta {G}^{o}$ and ${E}_{\mathrm{cell}}^{o}$ is

$\Delta {G}^{o}=-{\mathrm{nFE}}_{\mathrm{cell}}^{o}$

${\mathrm{FeO}}_{4}^{2-}\overset{+2.2V}{\longrightarrow }{\mathrm{Fe}}^{3+}{\Delta G}_{1}^{o}=-6.6F$ (3 electrons are involved)

${\mathrm{Fe}}^{3+}\overset{+0.70V}{\longrightarrow }{\mathrm{Fe}}^{2+}{\Delta G}_{2}^{o}=-0.7F$ (one electron is involved)

Hence, for

${\mathrm{FeO}}_{4}^{2-}\longrightarrow {\mathrm{Fe}}^{2+}{\Delta G}_{3}^{o}=-7.3F$

$=-{\mathrm{nFE}}_{\mathrm{cell}}^{o}$ (Four electrons are involved)

${E}_{{\mathrm{FeO}}_{4}^{2-}/{\mathrm{Fe}}^{+2}}^{0}=\frac{-7.3F}{-4F}=1.825,n=4$

$=1825\times {10}^{-3}V$

$n=$ Electron exchange of that half cell reaction.

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Solution

The relation between $\Delta {G}^{o}$ and ${E}_{\mathrm{cell}}^{o}$ is

$\Delta {G}^{o}=-{\mathrm{nFE}}_{\mathrm{cell}}^{o}$

${\mathrm{FeO}}_{4}^{2-}\overset{+2.2V}{\longrightarrow }{\mathrm{Fe}}^{3+}{\Delta G}_{1}^{o}=-6.6F$ (3 electrons are involved)

${\mathrm{Fe}}^{3+}\overset{+0.70V}{\longrightarrow }{\mathrm{Fe}}^{2+}{\Delta G}_{2}^{o}=-0.7F$ (one electron is involved)

Hence, for

${\mathrm{FeO}}_{4}^{2-}\longrightarrow {\mathrm{Fe}}^{2+}{\Delta G}_{3}^{o}=-7.3F$

$=-{\mathrm{nFE}}_{\mathrm{cell}}^{o}$ (Four electrons are involved)

${E}_{{\mathrm{FeO}}_{4}^{2-}/{\mathrm{Fe}}^{+2}}^{0}=\frac{-7.3F}{-4F}=1.825,n=4$

$=1825\times {10}^{-3}V$

$n=$ Electron exchange of that half cell reaction.

JEE Main 2023 — Chemistry Physical Chemistry

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Solution

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JEE Main 2023 — Chemistry Physical Chemistry

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

More JEE Main Physical Chemistry questions

Other Chemistry topics for JEE Main

Organic Chemistry

Inorganic Chemistry

Keep practicing Physical Chemistry