For ${{\rm{I}}_2} + 2{\rm{e}} \to 2{{\rm{I}}^ - }$, standard reduction potential = + 0.54 volt. For $2{\rm{B}}{{\rm{r}}^ - } \to {\rm{B}}{{\rm{r}}_2} + 2{{\rm{e}}^ - }$ , standard oxidation potential = - 1.09 volt. For ${\rm{Fe}} \to {\rm{F}}{{\rm{e}}^{2 + }} + 2{{\rm{e}}^ - }$, standard oxidation potential = + 0.44 volt. Which of the following reactions is non-spontaneous?

${{\rm{I}}_2} + 2{\rm{B}}{{\rm{r}}^ - } \to 2{{\rm{I}}^ - } + {\rm{B}}{{\rm{r}}_2}$

${\rm{B}}{{\rm{r}}_2} + 2{{\rm{I}}^ - } \to 2{\rm{B}}{{\rm{r}}^ - } + {{\rm{I}}_2}$

${\rm{Fe}} + {\rm{B}}{{\rm{r}}_2} \to {\rm{F}}{{\rm{e}}^{2 + }} + 2{\rm{B}}{{\rm{r}}^ - }$

${\rm{Fe}} + {{\rm{I}}_2} \to {\rm{F}}{{\rm{e}}^{2 + }} + 2{{\rm{I}}^ - }$

NEET UG CHEMISTRY MCQ: ELECTRO CHEMISTRY

1 Hard

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Application +4 | -1

For

{\mathrm{I}_2} + 2\mathrm{e} \to 2{\mathrm{I}^ - }

, standard reduction potential = + 0.54 volt. For

2\mathrm{B}{\mathrm{r}^ - } \to \mathrm{B}{\mathrm{r}_2} + 2{\mathrm{e}^ - }

, standard oxidation potential = - 1.09 volt. For

\mathrm{Fe} \to \mathrm{F}{\mathrm{e}^{2 + }} + 2{\mathrm{e}^ - }

, standard oxidation potential = + 0.44 volt. Which of the following reactions is non-spontaneous?

View answer and explanation

Correct option: D

{\mathrm{I}_2} + 2\mathrm{B}{\mathrm{r}^ - } \to 2{\mathrm{I}^ - } + \mathrm{B}{\mathrm{r}_2}

Option D (

{\mathrm{I}_2} + 2\mathrm{B}{\mathrm{r}^ - } \to 2{\mathrm{I}^ - } + \mathrm{B}{\mathrm{r}_2}

) is correct because the overall cell potential for this reaction is negative, indicating a non-spontaneous process.