Which of the following method for the measurement of osmotic pressure uses a porcelain tube having copper ferrocyanide membrane in its walls enclosed in a metallic jacket?

Berkeley-Hartley's method

The answer is (3) Berkeley-Hartley's method.

Berkeley-Hartley's method is a method for the measurement of osmotic pressure that uses a porcelain tube having a copper ferrocyanide membrane in its walls enclosed in a metallic jacket. The copper ferrocyanide membrane is a semipermeable membrane that allows water molecules to pass through it, but prevents the passage of solute molecules.

The porcelain tube is filled with the solution whose osmotic pressure is to be measured, and the metallic jacket is filled with a reference solution. The difference in the pressure between the two solutions is measured, and this difference is equal to the osmotic pressure of the solution.

The other methods listed are not used to measure osmotic pressure using a copper ferrocyanide membrane. Pfeffer's method uses a semipermeable membrane made of collodion, and De varies method uses a semipermeable membrane made of parchment paper.