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Question
Account for the following:
E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+.
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Solution 1
In case of Mn '+2' oxidation state is more stable than '+3' oxidation state and in case of Cr '+3' oxidation state is more stable than '+2' oxidation state.
Solution 2
The E° value for the Mn3+/Mn2+ couple is much more positive than that for the Cr3+/Cr2+ couple. This is because the Mn2+ ion is particularly stable due to the extra stability of its half-filled valence electronic configuration (3d5). Thus Mn3+ ion has a very high tendency to gain an electron and form the much more stable Mn2+ ion.
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RELATED QUESTIONS
|
`E_((M^(2+)/M)` |
Cr | Mn | Fe | Co | Ni | Cu |
| -0.91 | -1.18 | -0.44 | -0.28 | -0.25 | -0.34 |
From the given data of E0 values, answer the following questions :
(1) Why is `E_(((Cu^(2+))/(Cu)))` value exceptionally positive
(2) Why is `E_(((Mn^(2+))/(Mn)))` value is highly negative as compared to other elements
(3) Which is the stronger reducing agents Cr2+ or Fe2+ ? Give Reason.
For M2+/M and M3+/M2+ systems, the EΘ values for some metals are as follows:
| Cr2+/Cr | −0.9 V |
| Mn2+/Mn | −1.2 V |
| Fe2+/Fe | −0.4 V |
| Cr3/Cr2+ | −0.4 V |
| Mn3+/Mn2+ | +1.5 V |
| Fe3+/Fe2+ | +0.8 V |
Use this data to comment upon:
The stability of Fe3+ in acid solution as compared to that of Cr3+ or Mn3+.
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Transition metals and their compounds act as catalysts.
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The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of \[\ce{Cr^{3+}}\] ion is ______.
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Reason (R): Because it has positive electrode potential.
Which of the following is non-metallic?
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