Describe the oxidising action of potassium dichromate and write the ionic equations of reaction with:
(i). Iodide
(ii). Iron (II) solution and
(III). `H_2S`

Explanation

`{:((i),"iodide",Cr_(2)O_(7)^(2-)+14H^(+)+6I^(-)to2Cr^(3+)7H_(2)),((ii),"iron (II)solution",Cr_(2)O_(7)^(2)+14H^(+)+6Fe^(2+)rarr2Cr^(3+)+7H_(2)O+6Fe^(3+)),((ii),H_(2)S,Cr_(2)O_(7)^(2-)+8H^(+)+3H_(2)Srarr2Cr^(3+)+7H_(2)O+3S):}`