Question

explain Barkley and Hartley method

Answer 1

Various methods are employed for the measurement of osmotic pressure but the best known method was suggested by Berkeley and Hartley. A porcelain tube having copper ferrocyanide membrane in its walls in enclosed in a metallic jacket. The porcelain tube is fitted with a reservoir of pure solvent at one end and a capillary tube at the other end. In a metallic jacket is an arrangement for applying external pressure which is measured with the help of pressure eggs.



Procedure - The porcelain tube is filled with pure solvent and the metallic jacket with solution. The level in the capillary tube will tend to move down as the solvent flows towards solution due to osmosis. External pressure is now applied on the solution by the piston so that level in capillary remains stationary. The reading of pressure gauge is recorded. This is the osmotic pressure of the solution.

hope it helps

Answer 2

Movement of Solvent - Osmosis

Explanation:

Berkeley and Hartley.

• The apparatus used is shown in Fig. attached
• A porcelain tube having copper ferrocyanide membrane in its walls enclosed in a metallic jacket.  

• A reservoir (containing pure solvent at one end)being attached with a porcelain tube, and a capillary tube at another end.

• With the help of pressure eggs, we'll measure the external pressure being applied over the metallic jacket.

Process -

1. As the jacket is filled with a solution and pure solvent is poured in a porcelain tube.
2. With the solvent moving towards the solution (Osmosis Process), the level inside the capillary tube tends to move down or decreases.
3. On the application of external pressure towards the solution from the piston end, the level in capillary would not move or remains stationary.

The Osmotic Pressure of solution is being finalized by the reading at the pressure gauge