5-17. A sample of an antihistamine, brompheniramine maleate, weighing 4.6330 g was dissolved in alcohol and decomposed with metallic sodium. The resulting solution was treated with 10.00 mL of 0.2500 M AgNO3, an amount sufficient to precipitate all of the liberated bromide ion as AgBr. The excess AgNO3 was titrated with 0.1214 M KSCN, requiring 14.42 mL to reach the end point: Ag+ +SCN-â AgSCN (s) Calculate the % Br in the sample. what additional piece of information is needed to deter- mine the percentage of the antihistamine in the sample?