Question

Define : Isotonic solution

Hint:

For competitive exams, remember that \( 0.9% \) (mass/volume) NaCl solution is isotonic with human blood. This is why saline drips are prepared at this specific concentration.

Answer 1

Step 1: Understanding the Concept:
Osmotic pressure depends on the molarity of the solution. When two solutions are separated by a semi-permeable membrane and no net flow of solvent occurs, they are isotonic.
Step 3: Detailed Explanation:
Two solutions of different substances are called isotonic if they have the same molar concentration (\(C_1 = C_2\)) at the same temperature.
Since \(\pi = CRT\), if concentrations and temperatures are the same, their osmotic pressures (\(\pi\)) will be identical.
Example: \(0.91% (w/v)\) \(NaCl\) solution is isotonic with human red blood cells.
Step 4: Final Answer:
Isotonic solutions have equal osmotic pressure.