Q.Answer the following question.
Explain Electrophoresis in brief with the help of diagram. What are its applications?

Step 1. Set-up. In the electrophoresis apparatus (Fig 11.10), two platinum electrodes are dipped into a U-tube containing the colloidal solution, and an electric potential is applied across them.

Step 2. Diagram (described). The colloidal solution fills the U-tube; a cathode is at one end/arm and an anode at the other. Colloidal particles, all carrying the same sign of charge, are shown migrating through the solution toward the electrode of opposite sign, and 'deposited particles' build up at that electrode as the particles arrive, are discharged, and settle.

Step 3. What happens. Under the applied field, positively-charged colloidal particles move toward the cathode (negative electrode) and negatively-charged particles move toward the anode (positive electrode); on reaching the electrode they lose their charge and are deposited there. This movement of colloidal particles under an applied electric potential is, by definition, electrophoresis.

Step 4. Applications. (i) The direction a sol's particles migrate reveals the sign of the charge they carry. …

Describing the electrophoresis apparatus and mechanism (Section 11.9.5) and lis …

• Reversing which electrode attracts which charge -- positive particles move to the CATHODE, not the anode. …