Question

A 150 mL 0.25 M NaCl Solution, 250 mL 0.45 M CaCl₂ Solution and a 100 mL 0.60 M AlCl₃ Solution are mixed together and diluted to a final volume of 750 mL by adding enough water. Determine molarity of chloride ion (Cl^-) in Solution assuming that all three salts are completely soluble as well as completely dissociated.

Answer 1

First we need to calculate total mmoles of Cl^- from the three salt Solutions: 

mmoles of Cl^- ion from NaCl = 37.5 

mmoles of Cl^- ion from CaCl₂ = 2 x 112.5 = 225 

mmoles of Cl^- ion from AlCl₃ = 3 x mmoles of AlCl₃ = 3 x 60 = 180 

mmoles of Cl^- in final Solution = 37.5 + 225 + 180 = 442.5