Question

The method which is used to measure the osmotic pressure of a solution quickly and accurately is:
A.Berkeley-Hartley’s method
B.De varies method
C.Pfeffer’s method
D.All of the above

Answer 1

Hint: Osmotic pressure is the minimum amount of pressure applied to the solution to just prevent the inward flow of pure solvent molecules through the semipermeable membrane. When an external pressure is applied the osmotic pressure can be measured quickly and the method using this technique is known as Berkeley-Hartley’s method.

Complete answer:
Osmotic pressure is one of the colligative properties. Colligative properties are the properties of solutions that depend upon the concentration of solute or ion but not upon the nature or identity of solute particles.
Osmotic pressure, relative lowering of vapor pressure, depression in freezing point and elevation in boiling point are the four colligative properties and can be measured by different methods.
Osmotic pressure can be measured by different methods like Berkeley-Hartley’s method, De varies method and Pfeffer’s method.
Out of these three methods, Berkeley-Hartley’s method measures the osmotic pressure quickly. As in this method an external pressure is applied and useful in measuring the osmotic pressure quickly.
Hence, option (A) is the correct answer.

Note:
All the above methods are useful in calculating the osmotic pressure only. But in the Berkeley-Hartley’s method external pressure makes the measure of osmotic pressure quickly, whereas in the remaining methods there are no external pressure applications which leads to the slow measurement of osmotic pressure.