InterviewSolution
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InterviewSolution
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(a) Complete the following equation : (i) `CrO_(4)^(2-)+2OH^(-)rarr` (ii) `MnO_(4)^(-)+4H^(+)+3e^(-)rarr` (b) Account for the following : (i)Zn is not considered as transition element (ii) Transition metals form a large number of complexes (iii) The `E^(@)` value for the `(Mn^(3+))/(Mn^(2+))` couple is much more positive than for `(Cr^(3+))/(Cr^(2+))`couple. |
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Answer» (a)(i)`Cr_(2)O_(7)^(-2)+2OHrarr2crO_(4)^(-2)+H_(2)O` (ii)`MnO_(4)+4H+3e^(-)rarrrMnO_(2)+2H_(2)O` (b) (i) Because Zn has complelety filled d orbital (ii) Smaller sizes of metal ion high ionic changes vacant d orbital (iii) `Mn^(3+)` less stable than `Mn^(2+)`(3ds) which is stabel half filled configuration `Cr^(3+)` has stable `t_(22)g^(3)` configureation `Cr^(3+)` cannot reduce to `Cr^(2+)` (i) with reference to structural variabliltiy and chemical reactivity write the differenence between lanthanoids and actinoids (ii) Name a memeber of the lanthanoid series which is well known to exhibit + 4 oxidation state (iii) Complelte the following equation : `MnO_(4)^(-)+8H^(+)+5e^(-)rarr` (iv) out of `Mn^(+)` and `Cr^(3+)` which is more paramagnetic and why ? Atomic nos : Mn =25 Cr =24 |
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