In an analytical determination of aresenic , a solution containing aresenious acid, (H_(3)AsO_(3)). KI and a small amount of starch is electrolysed. The electrolysis produes free I_(2) from I^(-) ion and the I_(2) immediately oxidises the arsenious acid to hydrogen arsenate ion, (HAsO_(4)^(2-)). I_(2(aq.))+H_(3)AsO_(3(aq.))+H_(2)O_((l))rarr2I_((aq.))^(-)+HAsO_(4(aq.))^(2-)+4H_((aq.))^(+) When the oxidation of arsenic is complete, the free iodine combines with thestarch to give a deep blue colour.If during a particular run, it takes 65.3 s for a current of 10.5 mA to give an end point (indicated by the blue colour), how many grams of arsenic and H_(3)AsO_(3) are present in the solution? ("At. wt. of "As = 75)

In an analytical determination of aresenic , a solution containing are

1.	In an analytical determination of aresenic , a solution containing aresenious acid, (H_(3)AsO_(3)). KI and a small amount of starch is electrolysed. The electrolysis produes free I_(2) from I^(-) ion and the I_(2) immediately oxidises the arsenious acid to hydrogen arsenate ion, (HAsO_(4)^(2-)). I_(2(aq.))+H_(3)AsO_(3(aq.))+H_(2)O_((l))rarr2I_((aq.))^(-)+HAsO_(4(aq.))^(2-)+4H_((aq.))^(+) When the oxidation of arsenic is complete, the free iodine combines with thestarch to give a deep blue colour.If during a particular run, it takes 65.3 s for a current of 10.5 mA to give an end point (indicated by the blue colour), how many grams of arsenic and H_(3)AsO_(3) are present in the solution? ("At. wt. of "As = 75)
Answer» ANSWER :As `= 2.66 XX 10^(-4)g`, `H_(3)AsO_(3) = 5.0 xx 10^(-4)g ;`