Question

Migration of colloidal particles under the influence of electric field is called: (a) Browian movement (b) cataphoresis (c) dialy sis

Short answer

(b) cataphoresis

Step-by-step solution

Identify the Phenomenon

The phenomenon described in the question is the movement of colloidal particles when influenced by an electric field.

Matching the Phenomenon to the Correct Choice

This phenomenon is known as cataphoresis. Therefore the correct answer is option (b) cataphoresis.

Key concepts

Colloidal Particles

Colloidal particles are very small particles that remain dispersed in a medium without settling. Their sizes typically range from 1 nanometer to 1 micrometer. Colloidal systems can be found in various forms such as suspensions, emulsions, and foams.
Colloidal particles carry a charge that keeps them stable and dispersed, preventing them from clumping together. This stability is crucial for keeping substances like paint, milk, and ink consistent in texture.
- They are not large enough to settle by gravity. - Their interaction with light can cause effects like the Tyndall effect, where light is scattered through the colloid.
Understanding colloidal particles helps in studying their behavior, such as their reaction to an electric field, which is central to the migration phenomenon discussed in cataphoresis.

Electric Field

An electric field is a region around a charged object where other charges experience a force. It can be visualized with field lines that move from a positive charge towards a negative charge. The concept of an electric field is fundamental in physics and explains how charged particles interact over a distance.
Electric fields can be generated by a stationary or moving charge and can influence particles within the field. In the context of colloidal particles, exposing them to an electric field can result in movement known as cataphoresis. This movement is significant in technologies like electrophoresis, which is used in laboratories to separate molecules.
Key points about electric fields include: - They have a magnitude and direction. - Electric field strength is measured in volts per meter (V/m).
The way in which colloidal particles move through an electric field is governed by this concept, and it's fascinating to see how these invisible forces create observable effects.

Migration Phenomenon

The migration phenomenon in colloids occurs when these tiny particles move through a medium due to an external force, primarily an electric field. This specific type of migration is referred to as cataphoresis.
During cataphoresis, an electric field causes charged colloidal particles to migrate towards the electrode with the opposite charge. This is useful in various applications, such as in the separation and purification of substances in scientific and industrial processes.
- Cataphoresis aligns particles in a particular direction, facilitating their travel. - This process is different from Brownian movement, which is random due to thermal energy.
By carefully tuning the electric field, one can achieve precise control over the movement of particles, making this phenomenon a powerful tool in chemistry and materials science.