Calculate the n- factor of reactants in the given chemical changes?
(a) `K_(2)Cr_(2)O_(7)overset(H^(+))rarr Cr^(+3)`

Explanation

(i) In this reaction, `KMnO_(4)` which is an oxidizing agent, itself gets reduced to `Mn^(2+)` under acidic conditions.
`n = |1 xx (+7) - 1 xx (+2)| = 5 `
(ii) In this reaction, `KMnO_(4) ` gets reduced to `Mn^(4+)` under neutral or slightly (weakly) basic conditions.
`n = | 1 xx (+7) - 1 xx (+4) | = 3`
(iii) In this reaction, `KMnO_(4)` gets reduced to `Mn^(6+) ` under basic conditions.
`n = |1 xx (+7) - 1 xx (+6) | = 1`
(iv) In this reaction, `K_(2)Cr_(2)O_(7)` which acts as an oxidizing agent gets reduced to `Cr^(3+)` under acidic conditions. (It does not react under basic conditions ) .
` n = | 2 xx (+6) -2 xx (+3) | = 6 `
(v) In this reaction , `C_(2)O_(4)^(2-) ` (oxalate ion) gets oxidized to `CO_(2)` when it is reacted with an oxidizing agent .
`n = |2 xx (+3) - 2 xx (+4) | = 2 `
(vi) In this reaction , ferrous ions get oxidized to ferric ions.
`n |1 xx (+2) - 1 xx (+3) | = 1`
(vii) In this reaction, ferric ions are getting reduced to ferrous ions.
`n = | 2 xx (+3) - 2 xx (+2) | = 2`