Write complete equations for
(i) Oxidation of `Fe^(2+)` by `Cr_(2)O_(7)^(2-)` in acidic medium.
(ii) Oxidation of `S_(2)O_(3)^(2-)` by `MnO_(4)^(-)` in neutral aqueous medium.

Explanation

(i) Molecular equation
`K_(2)Cr_(2)O_(7)+7H_(2)SO_(4)+6FeSO_(4)to K_(2)SO_(4)+Cr_(2)(SO_(4))_(3)+3Fe_(2)(SO_(4))_(3)+7H_(2)O`
Ionic equation :
`Cr_(2)O_(7)^(2-)+6Fe^(2+)+14H^(+)to2Cr^(3+)+6Fe^(3+)+7H_(2)O`
(ii) Molecular equation :
`8KMnO_(4)+3Na_(2)S_(2)O_(3)+H_(2)O to 3K_(2)SO_(4)+8MnO_(2)+3Na_(2)SO_(4)+2KOH`
Ionic equation :
`8MnO_(4)^(-)+3S_(2)O_(3)^(2-)+H_(2)O to 8MnO_(2)+6SO_(4)^(2-)+2OH^(-)`