Home
Class 12
CHEMISTRY
Give reasons : (a) E^(@) value for Mn^...

Give reasons :
(a) `E^(@)` value for `Mn^(3+)//Mn^(2+)` couple is much more positive than that for `Fe^(3+)//Fe^(2+)`.
(b) Iron has higher enthalpy of atomisation than that of copper.
( c ) `Sc^(3+)` is colourless in aqueous solution whereas `Ti^(3+)` is coloured.

Text Solution

Verified by Experts

(a) `E^(@)` value for `Mn^(3+)//Mn^(2+)` couple is much more positive than that for `Fe^(3+)//Fe^(2+)`.
Electronic configurations of `Mn^(3+)` is `-3d^(4)` and that of `Mn^(2+)` is `-3d^(5)`. Thus `Mn^(3+)` has a tendency to gain one electron and change to more stable half-filled configuration to give `Mn^(2+)`. Thus it has a higher value of `E^(@)`.
Electronic configurations of `Fe^(3+)` is `-3d^(5)` and that of `Fe^(2+)` is `-3d^(6).Fe^(3+)` has a more stable half-filled configuration and has no tendency to gain an electron to change into `Fe^(2+)`.
Therefore `E^(@)` value for `Mn^(3+)//Mn^(2+)` couple is much more positive than for `Fe^(3+)//Fe^(2+)`.
(b) Iron has higher enthalpy of atomisation than that of copper. Enthalpy of atomisation depends upon the number of electrons in the outermost orbit. Iron has a higher enthalpy of atomisation than that of copper.
( c ) `Sc^(3+)` is colourless in aqueous solution whereas `Ti^(3+)` is coloured. Colour of a transition metal compound is due to d-d transition. Configuration of `Sc^(3+)` is [Ar]. There are no d-electrons and therefore there is no possibility of d-d transitions. Hence `Sc^(3+)` is colourless in aqueous solution. Configuration of `Ti^(3+)` is `3d^(1)`. There is a possibility of d-d transition. Hence this is coloured.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • THE D-AND F-BLOCK ELEMENTS

    U-LIKE SERIES|Exercise LONG ANSWER QUESTIONS-II (5 marks each)|21 Videos

  • THE D-AND F-BLOCK ELEMENTS

    U-LIKE SERIES|Exercise SELF ASSESSMENT TEST (SECTION A ) MULTIPLE CHOICE QUESTIONS (CHOOSE THE CORRECT OPTION)|7 Videos

  • THE D-AND F-BLOCK ELEMENTS

    U-LIKE SERIES|Exercise SHORT ANSWER QUESTIONS (2 marks each)|42 Videos

  • SURFACE CHEMISTRY

    U-LIKE SERIES|Exercise SELF ASSESSMENT TEST ( SECTION A)|7 Videos

  • THE P-BLOCK ELEMENTS

    U-LIKE SERIES|Exercise SELF ASSESSMENT TEST ( SECTION A)|7 Videos

Similar Questions

Explore conceptually related problems

Sc^(3+) is colourless is aqueous solution whereas Ti^(3+) is coloured.

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) Iron has higher enthalpy of atomization then that of copper. (c) Sc^(3+) is colourless in aqueous solution whereas Ti^(3+) is coloured.

Give reasons: E^0 value for Mn^(3+)//Mn^(2+) couple is much more positive than that for Fe^(3+)//Fe(2+) .

Give reasons: Iron has higher enthalpy of atomisation than of copper

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

Why is the E^(@) values for Mn^(3+)//Mn^(2+) couple much more positive than for Cr^(3+) // Cr^(2+) or Fe^(3+)//Fe^(2+)

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

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

Why is the E^(Theta) value for the Mn^(3+)//Mn^(2+) couple much postive than for Cr^(3+)//Cr^(2+) or Fe^(3+)//Fe^(2+) ? Example

Explain why (i) E^(@) for Mn^(3+)//Mn^(2+) couple is more positive than that for Fe^(3+)//Fe^(2+) ? (ii) Ce^(3+) can be easily oxidised to Ce^(4+) ? [Atomic numbers : Mn = 25, Fe = 26 Ce = 58]

Home
Profile