Pyrolusite is the main ore of manganese in which it is present as Its Mn content is determined by reducing it under acidic condition to `Mn^(2+)` with the help of oxalate `(C_(2)O_(4)^(2-))` ion which in turn gets oxidized to `CO_(2)` The analytical determination is carried out by adding a known excess volume of `(C_(2)O_(4)^(2-))` solution to a suspension of the pyrolusite and digesting the mixture on a hot water bath until all the `MnO_(2)` has been reduced. The excess unreacted oxalate solution is then titrated with standardized `KMnO_(4)` solution. Thereby Mn content of ore can be calculated. `KMnO_(4)`solution is also standardized under acidic condition against oxalate ion wherein `MnO_(4)^(-)` ion is reduced to `Mn^(2+)` and `(C_(2)O_(4)^(2-))` ion is oxidized to `CO_(2)`
Q sample containing `MnO_(2)` is treated with HCl liberating `Cl_(2)` The `Cl_(2)` is passed into a solution of KI and `30cm^(3)` of hypo is required to titrate the liberated iodine. What is the percentage of `MnO_(2)` in the sample ?

Options

A. `22.64%`
B. `26.1%`
C. `62.2%`
D. `72.5%`

Answer

B

Explanation

`MnO_(2)+4HCItoMnCl_(2)+2H_(2)O+Cl_(2)`
`Cl_(2)+2KIto2KCl+I_(2)`
Reaction involed
`I_(2)+2S_(2)O_(3)^(2-)to2I+S_(4)O_(6)`