Explain why colloids can be separated only by special filter papers and not by ordinary filter papers used to separate the solid from liquid.

Explanation

**Step-by-Step Solution:**

1. **Understanding Colloids:**
- Colloids are mixtures where tiny particles (called colloidal particles) are dispersed throughout another substance (usually a liquid). The size of these particles typically ranges from 1 to 1000 nanometers.

2. **Ordinary Filter Paper:**
- Ordinary filter paper is designed to separate larger solid particles from liquids. The pore size of ordinary filter paper is approximately 11,000 nanometers.

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