What is the molarity of a solution prepared by dissolving 8.4 grams of NaF (molar mass = 42 grams/mol) in enough water to make 100 mL of solution?

• A. 0.20 M
• B. 0.50 M
• C. 1.0 M
• D. 2.0 M

Answer: (D)

Verified step by step guidance

1. Identify the given information: mass of NaF = 8.4 grams, molar mass of NaF = 42 grams/mol, and volume of solution = 100 mL.
2. Convert the volume from milliliters to liters because molarity is expressed in moles per liter. Use the conversion: \(\text{Volume (L)} = \frac{\text{Volume (mL)}}{1000}\).
3. Calculate the number of moles of NaF using the formula: \(\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}\).
4. Use the molarity formula to find the concentration: \(M = \frac{\text{moles of solute}}{\text{liters of solution}}\).
5. Substitute the values for moles and volume in liters into the molarity formula to find the molarity of the NaF solution.