Massachusetts Pharmacy Technician License Practice Test

What concentration of sodium chloride solution is considered hypertonic?

1. 0.45%

2. 0.9%

3. 5.0%

4. 9.00%

The correct answer is: 9.00%

A sodium chloride solution is classified as hypertonic when its concentration is higher than that of the physiological saline solution, which is typically around 0.9% sodium chloride. A hypertonic solution causes water to move out of cells through osmosis, leading to cell shrinkage as they attempt to achieve equilibrium. In this context, a concentration of 9.00% sodium chloride is significantly above the normal physiological level. Such a concentrated solution would draw water out of cells, clearly categorizing it as hypertonic in relation to the body’s cells and fluids. Options with lower concentrations like 0.45%, 0.9%, or even 5.0% do not exceed the isotonic range and would not have the same osmotic effect on cells, which is why they are not considered hypertonic.