Practicing Success

Target Exam

CUET

Subject

Chemistry

Chapter

Physical: Electro Chemistry

Question:

\(Cr_2O_7^{2–} + I^– \rightarrow I_2 + Cr^{3+}\), \(E^o_{cell} = 0.79 V\), \(E^o_{Cr_2O_7^{–2}|Cr^{+3}} = 1.33 V\), \(E^o_{I_2| I^-}= ?\)

Options:

0.54

–0.054

+0.18 V

–0.18 V

Correct Answer:

0.54

Explanation:

The correct answer is option 1. 0.54.

To find the standard electrode potential (\(E^o_{I_2| I^-}\)) for the reaction \(I_2 + 2I^- \rightarrow 2I^-\), we can use the Nernst equation:

\(E^o_{cell} = E^o_{Cr_2O_7^{2-}|Cr^{3+}} - E^o_{I_2| I^-}\)

Given that \(E^o_{cell} = 0.79 V\) and \(E^o_{Cr_2O_7^{2-}|Cr^{3+}} = 1.33 V\), we can rearrange the equation to solve for \(E^o_{I_2| I^-}\):

\(E^o_{I_2| I^-} = E^o_{Cr_2O_7^{2-}|Cr^{3+}} - E^o_{cell}\)

\(E^o_{I_2| I^-} = 1.33 V - 0.79 V\)

\(E^o_{I_2| I^-} = 0.54 V\)

Therefore, the correct answer is (1) 0.54 V.