Match the items given in Column I and Column II.
`{:(,"Column I","Column II"),(A.,"Protective colloid",1.FeCl_(3)+NaOH),(B.,"Liquid-liquid colloid",2."Lyophilic colloids"),(C.,"Positively charged colloid",3."Emulsion"),(D.,"Negatively charged colloid",4.FeCl_(3)+"hot water"):}`

Explanation

To solve the matching question between Column I and Column II, we will analyze each item in Column I and find the appropriate match from Column II based on the properties of colloids.

### Step-by-Step Solution:

1. **Identify Protective Colloid (A)**:
- Protective colloids are typically lyophilic colloids that stabilize lyophobic colloids.
- They form a protective layer around the lyophobic particles.
- **Match**: A (Protective colloid) → 2 (Lyophilic colloids).

2. **Identify Liquid-Liquid Colloid (B)**:
- Liquid-liquid colloids are formed when one liquid is dispersed in another immiscible liquid, creating an emulsion.
- **Match**: B (Liquid-liquid colloid) → 3 (Emulsion).

3. **Identify Positively Charged Colloid (C)**:
- When FeCl3 is added to hot water, it forms a positively charged colloid due to the presence of Fe3+ ions.
- This results in the formation of hydrated ferric oxide, which is positively charged.
- **Match**: C (Positively charged colloid) → 4 (FeCl3 + hot water).

4. **Identify Negatively Charged Colloid (D)**:
- When FeCl3 is mixed with NaOH, a negatively charged colloid is formed due to the absorption of OH- ions.
- **Match**: D (Negatively charged colloid) → 1 (FeCl3 + NaOH).

### Final Matches:
- A → 2 (Protective colloid → Lyophilic colloids)
- B → 3 (Liquid-liquid colloid → Emulsion)
- C → 4 (Positively charged colloid → FeCl3 + hot water)
- D → 1 (Negatively charged colloid → FeCl3 + NaOH)

### Summary of Matches:
- A: 2
- B: 3
- C: 4
- D: 1

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