You are the leading chemist af Dedlee Stuph Ltd-a majormanufacturer and supplier of arsenictrioxide (As2 Oa), used in the production of colourless glass.

Transcribed Image Text:

You are the leading chemist at Dedlee Stuph Ltd- a major manufacturer and supplier of arsenic trioxide (As2O3), used in the production of colourless glass. You suspect that the latest lot off the line is not pure arsenic trioxide. You take 3 separate samples of approximately 0.15g and analyze them as follows: Quantitatively transfer each mass to separate 100.0mL volumetric flasks; dissolve in 25mL of dilute sodium hydroxide (aq); add -2mL of 3M sulfuric acid, then make to mark with DI water. For each sample, 10.00mL aliquots were removed and analyzed using indirect coloumetric titration with iodine. Your results were as follows: Mass of unknown (g) Time for reaction to be complete (s) Voltage Observed (V) Resistance of Set Up (Ohms) Mathematically, Trial 1 m= 0.1516 What is the percent of As2O3 in each trial? What is the average? Should you be concerned about this lot? q F• Z 254.7 • MW 1.270 100.0 Trial 2 0.1704 Helpful information: When arsenic trioxide is dissolved in water, it forms arsenious acid (H3ASO3): As2O3+ 3H2O 2H3ASO3 283.6 The half reaction for arsenious acid in the coulometric titration is: H3ASO3 + 4OH HASO4 + 3H₂O + 2e 1.272 100.0 (Hint: "q" can be related back to current and time... and voltage.) Trial 3 0.1632 271.1 1.284 100.0 You are the leading chemist at Dedlee Stuph Ltd- a major manufacturer and supplier of arsenic trioxide (As2O3), used in the production of colourless glass. You suspect that the latest lot off the line is not pure arsenic trioxide. You take 3 separate samples of approximately 0.15g and analyze them as follows: Quantitatively transfer each mass to separate 100.0mL volumetric flasks; dissolve in 25mL of dilute sodium hydroxide (aq); add -2mL of 3M sulfuric acid, then make to mark with DI water. For each sample, 10.00mL aliquots were removed and analyzed using indirect coloumetric titration with iodine. Your results were as follows: Mass of unknown (g) Time for reaction to be complete (s) Voltage Observed (V) Resistance of Set Up (Ohms) Mathematically, Trial 1 m= 0.1516 What is the percent of As2O3 in each trial? What is the average? Should you be concerned about this lot? q F• Z 254.7 • MW 1.270 100.0 Trial 2 0.1704 Helpful information: When arsenic trioxide is dissolved in water, it forms arsenious acid (H3ASO3): As2O3+ 3H2O 2H3ASO3 283.6 The half reaction for arsenious acid in the coulometric titration is: H3ASO3 + 4OH HASO4 + 3H₂O + 2e 1.272 100.0 (Hint: "q" can be related back to current and time... and voltage.) Trial 3 0.1632 271.1 1.284 100.0

Answer rating: 100% (QA)

Solution To determine the percent of As 2 O 3 in each trial and assess the situation we can follow these steps 1 Calculate the amount of charge q used ... View the full answer