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Balance the following redox reaction by using Oxidation number method in acidic medium.Cr_2O_7^-2(aq)+SO_3^_2(aq)rarrCr^+3(aq)+SO_4^-2(aq) |
Answer» Solution :`Cr_(2)O_(7)^(2-)+SO_(3)^(2-)toCr^(3+)+SO_(4)^(2-)`(Acidic medium)  `Cr_(2)O_(7)^(2-)overset(CANCEL(2)xx3"units")(to)2Cr^(3+)` Reduction `SO_(3)^(2-)overset(cancel(2)"units")(to)SO_(4)^(2-)` OXIDATION multiply reduction equation by 1 unit and oxidation equation by 3 units `Cr_(2)O_(7)^(2-)to2Cr^(3+)` `3SO_(3)^(2-)to3SO_(4)^(2-)` Adding both equation `Cr_(2)O_(7)^(2-)+3SO_(3)^(2-)to2Cr^(3+)+3SO_(4)^(2-)` SINCE there are 4 oxygen atom more on LHS, `4H_(2)O` is added on RHS. The equation is balanced WRT H+Ion. `Cr_(2)O_(7)^(2-o)+3SO_(3)^(2-)+8H^(+)to2Cr^(3+)+3SO_(4)^(2-)+4H_(2)O` |
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