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Why is the E^(ɵ) value for the Mn^(3+)//...

Why is the `E^(ɵ)` value for the `Mn^(3+)//Mn^(2+)` couple much more position than that for `Cr^(3+)//Cr^(2+)" ? Explain.

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To explain why the standard electrode potential (E°) value for the Mn³⁺/Mn²⁺ couple is much more positive than that for the Cr³⁺/Cr²⁺ couple, we can analyze the electronic configurations and stability of the ions involved. ### Step-by-Step Solution: 1. **Identify the Electronic Configurations**: - For **Mn³⁺**: The electronic configuration is [Ar] 3d⁴. - For **Mn²⁺**: The electronic configuration is [Ar] 3d⁵. - For **Cr³⁺**: The electronic configuration is [Ar] 3d³. ...
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How would you account for the following? (i)The atomic radii of the metals of the third (5d) series of transition elements are virtually the same as those of the corresponding members of the second (4d) series. (ii)The E^(@) value for the Mn^(3+)//Mn^(2+) couple is much more positive than that for Cr^(3+)//Cr^(2+) couple or Fe^(3+)//Fe^(2+) couple. (iii)The highest oxidation state of a metal is exhibited in its oxide or fluoride.

Assign reasons for the following : (i) The enthalpies of atomisation of transition elements are high. (ii) The transition metals and many of their compounds act as good catalyst. (iii) From element to element the actinoid contraction is greater than the lanthanoid contraction. (iv) The E^(@) value for the Mn^(3+)//Mn^(2+) couple is much more positive than that for Cr^(3+)//Cr^(2+) . (v) Scandium (Z = 21) does not exhibit variable oxidation states and yet it is regarded as transition element.

Why is the value for (Mn^(3+))/(Mn^(2+)) couple much more positive than that for (Cr^(3+))/(Cr^(2+)) or (Fe^(3+))/(Fe^(2+)) ? Explain

Give reason for the folloiwng : (a) E_("value")^(@) for Mn^(3+)//Mn^(2+) couple is much more positive than that of Fe^(3+)//Fe^(2+) couple. (b) Sc^(3+) is colourless in aqueous solution whereas Ti^(3+) is coloured.

Explain why E^(@) for Mn^(3+)//Mn^(2+) couple is more positive than that for Fe^(3+)//Fe^(2+) (At. Nos. Mn=25,Fe=26)?

(a) Account for the following : (i) Transition metals form large number of complex compounds (ii) The lowest oxide of transition metal is basic whereas the highest oxide is amphoteric or acidic (iii) E^(@) value for the Mn^(3+)//Mn^(2+) couple is highly positive (+1.57V) as compare to Cr^(3+)//Cr^(2+) (b) Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.

(a) Account for the following, (i) Transition metals show variable oxidation states. (ii) Zn, Cd and Hg are soft metals. (c) E^(@) value for the Mn^(3+)//Mn^(2+) couple is highly positive (+1.57V) as compared to Cr^(3+)//Cr^(2+) (b) Write one similarity and one difference the chemistry of lanthanoid and actinoid elements.

Assign reasons for the following: (a) Ce^(3+) can easily be oxidised to Ce^(4+) (b) E^(Theta) for Mn^(3+) | Mn^(2+) couple is more positive than Fe^(3+) | Fe^(2+) Explain the following : (a) Zr and Hf exhibit similar properties. (b) The colour of K_2Cr_2O_7 solution changes with the change in pH value of the solution .

E_(Mn^(3+)//Mn^(2+))^@ is highly positive than that of E_(Cr^(3+)//Cr^(2+))^@orE_(Fe^(3+)//Fe^(2+))^@ because

Assertion: E^(@) for Mn^(3+)//Mn^(2+) is more positive than Cr^(3+)//Cr^(2+) Reason: The third ionisation energy of Mn is larger than that of Cr .