Explain the terms 'Brownian movement' and 'peptization'.

Answer

### Step-by-Step Text Solution:

**Step 1: Define Brownian Movement**
- Brownian movement refers to the random and erratic motion of microscopic particles that are suspended in a fluid (liquid or gas). This motion is caused by the collision of the particles with the molecules of the dispersion medium.

**Step 2: Explain the Characteristics of Brownian Movement**
- The movement is characterized by its unpredictability and is observable under a microscope. It is a key feature of colloidal systems and is responsible for the stability of colloidal dispersions, preventing the particles from settling down.

**Step 3: Define Peptization**
- Peptization is the process through which freshly precipitated particles are converted into a colloidal form. This transformation is achieved by the addition of a suitable peptizing agent, which stabilizes the colloidal particles and prevents them from aggregating.

**Step 4: Explain the Role of Peptizing Agents**
- Peptizing agents are substances that help to disperse the particles in a medium, allowing them to remain suspended. Common peptizing agents include electrolytes or surfactants, which can alter the surface charge of the particles, thus enhancing their stability in the colloidal state.