The process of removing dissolved substance from a colloidal solution by means of diffusion through a suitable membrane is termed as…………..

Answer

To solve the question regarding the process of removing dissolved substances from a colloidal solution through diffusion, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Colloidal Solutions**:
- Colloidal solutions consist of tiny particles dispersed in a medium. These particles are larger than molecules but smaller than those in a suspension.

2. **Identifying the Process**:
- The question specifically asks about a method to remove dissolved substances (impurities) from a colloidal solution.

3. **Membrane Diffusion**:
- The process involves using a suitable membrane that allows certain particles to pass through while retaining others. In this case, the colloidal particles cannot pass through the membrane, but smaller impurities (like electrolytes) can.

4. **Defining Dialysis**:
- The process that fits this description is called **dialysis**. Dialysis utilizes a semi-permeable membrane (like a parchment membrane) to separate colloidal particles from smaller dissolved substances.

5. **Process Description**:
- In dialysis, the colloidal solution is placed in a dialysis bag (which acts as the membrane), and it is submerged in distilled water. Over time, the smaller impurities diffuse out of the colloidal solution into the distilled water, effectively purifying the colloid.

6. **Conclusion**:
- Therefore, the answer to the question is that the process of removing dissolved substances from a colloidal solution by means of diffusion through a suitable membrane is termed **dialysis**.

### Final Answer:
The process of removing dissolved substances from a colloidal solution by means of diffusion through a suitable membrane is termed as **dialysis**.