Question: What is the molarity of a solution prepared by dissolving 5 grams of NaCl in enough water to make 250 mL of solution? (Molar mass of NaCl = 58.5 g/mol) (2023)

Options:

1. 0.34 M
2. 0.42 M
3. 0.25 M
4. 0.50 M

Correct Answer: 0.34 M

Exam Year: 2023

Solution:

Molarity (M) = moles of solute / liters of solution. Moles of NaCl = 5 g / 58.5 g/mol = 0.0855 moles. Volume of solution = 250 mL = 0.250 L. M = 0.0855 moles / 0.250 L = 0.342 M, approximately 0.34 M.