Pyrolusite, MnO_(2), is the main ore from which manganese is produced. The manganese content of the ore may be determined by reducing the MnO_(2) under acetic conditions to Mn^(2+) with the oxalate ion, C_(2)O_(4)^(2-), the oxalate ion being oxidised to carbon dioxide during the reaction. The analytical determination is carried out by adding a known excess volume of oxalate 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 standardised potassium permanganate, KMnO_(4) solution after which the manganese content of the ore can be calculated. A student prepared a standard solution of sodium oxalate by weighing 3.2 g of the dry anhydrous salt, dissolving it in distilled water and making the solution up to 500 mL. 25 mL of the oxalate solution required 24.76 mL of KMnO_(4) solution. How many moles of C_(2)O_(4)^(2-) ions will be oxidised by 1 mole MnO_(4)^(-) ?