The quantity of antimony in a sample can be determined by an oxidation–reduction titration with an oxidizing agent. A 7.97 g sample of stibnite, an ore of antimony, is dissolved in hot, concentrated HCl(aq) and passed over a reducing agent so that all the antimony is in the form Sb3+(aq). The Sb3+(aq) is completely oxidized by 34.8 mL of a 0.130 M aqueous solution of KBrO3(aq). The unbalanced equation for the reaction is

BrO−3(aq)+Sb3+(aq)⟶Br−(aq)+Sb5+(aq)(unbalanced)

Calculate the amount of antimony in the sample and its percentage in the ore.


mass of antimony in grams:

percentage of antimony: