Final answer:
A normal saline solution contains 0.9% NaCl by mass/volume percent.
Step-by-step explanation:
A normal saline solution, commonly used in medical settings, contains 0.9% NaCl by mass/volume percent. This means that for every 100 mL of the solution, there are 0.9 grams of NaCl. For example, in a 1 liter bag of normal saline solution, there would be 9 grams of NaCl.