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Give the chemical reactions showing oxidizing nature of potassium dichromate |
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Answer» Solution :In acidic medium, the dichromate ion act as very good oxidizing agent.. The reaction can be represented as: `Cr_(2)O_(7)^(2-) + 14H^(+) + 6E^(-) rarr 2Cr^(3+) + 7H_(2)O (E^(@) = +1.33V)` Acidified dichromate solution oxidizes iodides to iodine, sulphides to sulphur, Sn(II) to Sn(IV), Fe(II) to Fe(III) etc. The half reactions of each species are: (i) `6I^(-) rarr 3I_(2) + 6e^(-)` (ii) `3H_(2)S rarr 6H^(+) + 3S+ 6e^(-)` (iii) `3Sn^(2+) rarr 3Sn^(4+) + 6e^(-)` (iv) `6Fe^(2+) rarr 6Fe^(3+) + 6e^(-)` The full ionic reaction can be obtained by adding half-reaction of potassium dichromate to the half reaction for the reducing agent Ex: `Cr_(2)O_(7)^(2-) + 14H^(+) + 6Fe^(2+) rarr 6Fe^(3+) + 2Cr^(3+) + 7H_(2)O` |
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