Can dispersion medium move in electrophoresis
Answers
Answer:
When the movement of dispersed phase of colloidal solution is prevented by suitable means, the dispersion medium can be made to move under the influence of an applied electric field or potential.
Answer:When the movement of dispersed phase of colloidal solution is prevented by suitable means, the dispersion medium can be made to move under the influence of an applied electric field or potential.
Electrophoresis
When a potential difference (electric field) is applied across two platinum electrodes immersed in a colloidal solution, the particles of dispersed phase move towards either the positive or negative electrode. This observation was first discovered by Rauss in 1807 and was investigated later by Linder and Picton.
The movement of colloidal particles under the action of electric field is known as Electrophoresis.
If the colloidal particles move towards the positive electrode (Anode) they carry negative charge. On the other hand if the sol particles migrate towards negative electrode (Cathode), they are positively charged. From the direction of movement of colloidal particles it is possible to find out the charge on colloidals.
Demonstration of Electrophoresis
The demonstration of electrophoresis is as follows:-
Take a colloidal sol say AS2S3 sol in a U – tube. Place an electrolyte, having density less than that of solution (say distilled water). The electrolyte provides distinct boundary between electrolyte and colloidal sol.
Place two platinum electrodes in two arms of U – tube such that they dip in the colloidal sol. When a high potential difference of about 100 volts is applied across the two platinum electrodes, it is observed that the level or Boundary of colloidal solution falls on the negative electrode side and rises up on positive electrode side. On reaching the positive electrode, the colloidal particles get discharged. As a result of neutralisation of charge, the colloidal particles aggregate and settle down at the bottom.