Chemistry - Redox Reactions Question with Solution | TestHub

12 g of an impure sample of arsenious oxide was dissolved in water containing 7.5 g of sodium bicarbonate and the resulting solution was diluted to 250 mL .25 mL of this solution was completely oxidized by 22.4 mL of a solution of iodine. 25 mL of this iodine solution reacted with same volume of a solution containing 24.8 g of sodium thiosulphate $\left({\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3\cdot 5{\mathrm{H}}_2\mathrm{O}\right)$ in one litre. Calculate the percentage of arsenious oxide in the sample. (Atomic mass of $\mathrm{As}=75$ ) Given: ${\mathrm{As}}_2{\mathrm{O}}_3$ reacts with ${\mathrm{NaHCO}}_3$ to give ${\mathrm{Na}}_3{\mathrm{AsO}}_3$.