An impure sample of As2O3 weighing 20 gm was dissolved in water containing 10 gm of NaHCO3 and the final solution was diluted to 400mL. 20 mL of this solution was oxidised by 25 mL of a solution of I2. Another solution of hypo containing 1.24 gm of Na2S2O3.5H2O in 40 mL was used to exactly reduce 25 mL of same I2 solution (impurities inert) calculate % of As2O3 in the sample (at. wt. of As = 75)

An impure sample of As2O3 weighing 20 gm was dissolved in water contai

1.	An impure sample of As2O3 weighing 20 gm was dissolved in water containing 10 gm of NaHCO3 and the final solution was diluted to 400mL. 20 mL of this solution was oxidised by 25 mL of a solution of I2. Another solution of hypo containing 1.24 gm of Na2S2O3.5H2O in 40 mL was used to exactly reduce 25 mL of same I2 solution (impurities inert) calculate % of As2O3 in the sample (at. wt. of As = 75)
Answer» An impure sample of $A s_{2} O_{3}$ weighing $20 g m$ was dissolved in water containing $10 g m o f N a H C O_{3}$ and the final solution was diluted to $400 m L$ . $20 m L$ of this solution was oxidised by $25 m L$ of a solution of $I_{2}$ . Another solution of hypo containing $1.24 g m$ of $N a_{2} S_{2} O_{3} .5 H_{2} O$ in $40 m L$ was used to exactly reduce $25 m L$ of same $I_{2}$ solution (impurities inert) calculate % of $A s_{2} O_{3}$ in the sample (at. wt. of As = 75)