Which of the following solutions has the highest mass/volume percent (% m/v)?

• A. 10 g NaCl dissolved in 200 mL water
• B. 10 g NaCl dissolved in 100 mL water
• C. 5 g NaCl dissolved in 100 mL water
• D. 5 g NaCl dissolved in 200 mL water

Answer: (B)

Verified step by step guidance

1. Understand that mass/volume percent (% m/v) is defined as the mass of solute (in grams) divided by the volume of the solution (in milliliters), multiplied by 100%. The formula is: \[\% m/v = \frac{\text{mass of solute (g)}}{\text{volume of solution (mL)}} \times 100\%\]
2. Calculate the % m/v for each solution by substituting the given values into the formula. For example, for 10 g NaCl in 200 mL water, compute \[\frac{10}{200} \times 100\%\].
3. Repeat the calculation for 10 g NaCl in 100 mL water, 5 g NaCl in 100 mL water, and 5 g NaCl in 200 mL water using the same formula.
4. Compare the calculated % m/v values for all four solutions to determine which one has the highest concentration.
5. Identify the solution with the highest % m/v as the one with the greatest mass of solute per volume of solution.