0.5109 g of pure mn powder was dissolved in 50 ml of nitric acid. this solution was quantitatively transferred to a 1 l volumetric flask and diluted to volume with di-water. next 30.00 ml solution was removed using a volumetric pipet and placed into a 100 ml beaker. 10 ml water, 5 ml of phosphoric acid, and 0.4 g of potassium periodate were then added. after the mn was oxidized to permanganate, the solution was quantitatively transferred to a 150 ml volumetric flask and diluted to volume with di-water. what is the concentration of this solution expressed in mg mn / 100 ml?