Which of the following statements are correct ?

Options

A. Mixing two oppositely charged sols neutralises their charges and stabilises the colloid
B. Presence of equal and similar charges on colloidal particles provides stability to the colloids
C. Any amount of dispersed liquid can be added to emulsion without destabilising it
D. Brownian movement stabilises sols

Answer

To determine which statements are correct regarding colloids and their stability, let's analyze each option step by step.

### Step 1: Analyze the First Statement
**Statement:** Mixing two oppositely charged salts neutralizes their charges and stabilizes the colloid.

**Analysis:**
- When two oppositely charged salts are mixed, they indeed neutralize each other's charges.
- However, this neutralization leads to destabilization of the colloid, as the particles may aggregate and precipitate out of the solution.

**Conclusion:** This statement is **incorrect**.

### Step 2: Analyze the Second Statement
**Statement:** Presence of equal and similar charges on colloidal particles provides stability to the colloids.

**Analysis:**
- If colloidal particles have equal and similar charges, they will repel each other due to electrostatic forces.
- This repulsion prevents the particles from coming together and aggregating, thus maintaining their dispersion in the medium.

**Conclusion:** This statement is **correct**.

### Step 3: Analyze the Third Statement
**Statement:** Any amount of dispersed liquid can be added to emulsion without destabilizing it.

**Analysis:**
- While emulsions can tolerate some addition of dispersed liquid, there is a limit to how much can be added before destabilization occurs.
- Adding too much of the dispersed phase can lead to separation and destabilization of the emulsion.

**Conclusion:** This statement is **incorrect**.

### Step 4: Analyze the Fourth Statement
**Statement:** Brownian movement stabilizes salts.

**Analysis:**
- Brownian movement refers to the random motion of particles suspended in a fluid, which helps to keep them dispersed.
- This movement can prevent the aggregation of colloidal particles, thus contributing to the stability of colloids.

**Conclusion:** This statement is **correct**.

### Final Answer
Based on the analysis:
- **Correct Statements:** Option 2 and Option 4.
- **Incorrect Statements:** Option 1 and Option 3.