(solution) A 3.67 g sample of insecticide was decomposed in acid, any As^5+

(solution) A 3.67 g sample of insecticide was decomposed in acid, any As^5+

A 3.67 g sample of insecticide was decomposed in acid, any As^5+ was reduced to As^3+and diluted to 250.0 mL in a volumetric flask. A 5.00 mL aliquot was added to 125.0mL of 0.0500 M KI buffered to pH 7. A coulometric titration was carried out withelectrically-generated I3^- (3I^- ? I3^- + 2e-) which oxidized As^3+ to As^5+ according tothe reaction.As^3+ + I3^- ? 3I^- + As^5+The titration required 287 s at a constant current of 24.25 mA to reach the en