The molecular weight of silver bromide (AgBr) is 187.77 g/mole. The presence of the ions in solution can be shown as- AgBr (insoluble) ⇄ + .
45.00 mL of the aliquot contains 0.6485 g of AgBr. Thus 1000 mL of the aliquot contains ×1000 = 14.411 gm-mole. Thus the solubility product of AgBr = []×.
Or, 5.0× = (the given value of solubility product of AgBr is 5.0× and the charge of the both ions are same).
Thus S = (5.00×) = 7.071× g/mL.
Thus the concentration of Br or HBr is 7.071× g/mL.