Pyrolusite is the main ore of manganese in which it is present asIts 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)Qof pyrolusite ore were treated withof pure ferrous ammonium sulphate FeSO_(4).(NH_(4))_(2)SO_(4)6h_(2)O) and dil. H_(2)SO_(4)After the reaction solution was diluted to.of dilute solution required 10 mL of 0.1NK_(2)Cr_(2)O_(7) solution. What is the amount of ferrous ammonium sulphate in 500 mL of solution, which is neutralized by K_(2)Cr_(2)O_(7)solution ?