Which of the following solutions contains the largest number of chloride ions?

• A. 250 mL of 0.5 M CaCl_2
• B. 1.0 L of 0.1 M KCl
• C. 750 mL of 0.1 M MgCl_2
• D. 500 mL of 0.2 M NaCl

Answer: (A)

Verified step by step guidance

1. Identify the number of chloride ions produced per formula unit of each compound when dissolved. For example, CaCl_2 dissociates into one Ca^{2+} ion and two Cl^{-} ions, so it produces 2 chloride ions per formula unit.
2. Calculate the number of moles of each compound in the given volume using the formula: \(\text{moles} = \text{molarity} \times \text{volume (in liters)}\).
3. Multiply the moles of each compound by the number of chloride ions produced per formula unit to find the total moles of chloride ions in each solution.
4. Compare the total moles of chloride ions calculated for each solution to determine which one contains the largest number of chloride ions.
5. Remember that the solution with the highest total moles of chloride ions corresponds to the largest number of chloride ions present.