Verified answer

NaCl dissociates as follows

NaCl ---> Na+ + Cl-

you can see that 1 NaCl produces 1 mol Cl-

So molarity NaCl = molarity Cl- = 0.1900 M

SrCl2 dissociates as follows

SrCl2 ---> Sr^2+ + 2Cl-

you can see that 2 Cl- ions are produced from each SrCl2

So molarity Cl- = 2 x molarity SrCl2 = 0.200 M

AlCl3 dissociates as follows

AlCl3 ---> Al^3+ + 3Cl-

you can see that each AlCl3 yields 3 Cl- ions

So molarity Cl- = 3 x molarity FeCl3

= 0.360 M