Which statement is true about a solution labeled as 2.0 M NaCl(aq)?

• A. It contains 2.0 moles of NaCl dissolved in 1.0 kilogram of water.
• B. It contains 2.0 moles of NaCl dissolved in 1.0 liter of solution.
• C. It contains 2.0 moles of NaCl dissolved in 1.0 liter of water.
• D. It contains 2.0 grams of NaCl dissolved in 1.0 liter of solution.

Answer: (B)

Verified step by step guidance

1. Understand that the concentration unit 'M' stands for molarity, which is defined as moles of solute per liter of solution.
2. Recall the formula for molarity: \(M = \frac{\text{moles of solute}}{\text{liters of solution}}\).
3. Note that the volume in molarity refers to the total volume of the solution, not just the solvent (water).
4. Recognize that a 2.0 M NaCl solution means there are 2.0 moles of NaCl dissolved in exactly 1.0 liter of the entire solution.
5. Therefore, the correct interpretation is that the solution contains 2.0 moles of NaCl dissolved in 1.0 liter of solution, not just water or by mass.