InterviewSolution
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InterviewSolution
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(a) Account for the following: (i) Ce^(4+) is a strong oxidising agent in aqueous solution. (ii) Transition metals have high enthalpy of atomisation. (iii) Mn shows maximum number of oxidation states in 3d series. (b) Complete the following equations: (i) 2MnO_(4)^(-)+6H^(+)+5NO_(2)^(-)to (ii) Cr_(2)O_(7)^(2-)+14H^(+)+6Fe^(2+)to |
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Answer» Solution :(a) (i) In aqueous solutions `Ce^(4+)` tends to CHANGE to `Ce^(3+)` as +3 oxidation state is more stable. Therefore `Ce^(4+)` acts as an oxidising agent. (ii) Transition metals have a large number of UNPAIRED electrons in their atoms. They form strong metallic bonds and therefore have a high enthalpy of atomisation. (iii) Mn has the electronic configuration `-3d^(5)4s^(2)`. It shows oxidation states from +2 to +7. It has the maximum number of unpaired electrons. (b) (i) `MnO_(4)^(-)+8H^(+)+5e^(-)to Mn^(2+)+4H_(2)O"]"xx2` `(NO_(2)^(-)+H_(2)O to NO_(3)^(-)+2H^(+)+2e^(-)"]"xx5)/(2MnO_(4)^(-)+5NO_(2)^(-)+6H^(+)to 2Mn^(+)+5NO_(3)^(-)+3H_(2)O)` (ii) `Cr_(2)O_(7)^(2-)+14H^(+)+6e^(-)to 2Cr^(3+)+7H_(2)O` `(FE^(2+)toFe^(3+)+E^(-)"]"xx6)/(Cr_(2)O_(7)^(2-)+6Fe^(2+)+14H^(+)to 2Cr^(3+)+6Fe^(3+)+7H_(2)O)` |
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