Answer : The correct option is, (b) 300. mL of 0.10 M CaCl₂
Explanation :
We have to calculate the number of moles of ions for the following aqueous solutions.
(a) 400. mL of 0.10 M NaCl
NaCl dissociates to give 2 moles of ions.
Volume of solution = 400. mL = 0.400 L
Total moles of ion = 0.04 mol × 2 = 0.08 mol
(b) 300. mL of 0.10 M CaCl₂
CaCl₂ dissociates to give 3 moles of ions.
Volume of solution = 300. mL = 0.300 L
Total moles of ion = 0.03 mol × 3 = 0.09 mol
(c) 200. mL of 0.10 M FeCl₃
FeCl₃ dissociates to give 4 moles of ions.
Volume of solution = 200. mL = 0.200 L
Total moles of ion = 0.02 mol × 4 = 0.08 mol
From this we conclude that, aqueous solutions contains the greatest number of ions.
Hence, the correct option is, (b) 300. mL of 0.10 M CaCl₂