Question

Arsenic in 7,150 g of a herbicide is converted in arsenate ions (AsO4{3-}) and the arsenate ions form a precipitate of Ag3AsO4 with 25,00 ml of AgNO3 solution 0,05000 M. The excess of Ag{+} is titrated with 3,85 ml of a KSCN solution 0,0500 M. Calculate the % concentration of arsenic in the sample.