Which of the following are negatively charged sols ?

Options

A. Gold sol
B. Prussian blue dye
C. Haemoglobin
D. Starch .

Answer

To determine which of the given options are negatively charged sols, we need to analyze each option based on the charge of the dispersed phase particles. Here's a step-by-step solution:

### Step 1: Understand the Concept of Sols
- A sol is a colloidal system where a solid (dispersed phase) is dispersed in a liquid (dispersion medium).
- The charge of the dispersed phase particles determines whether the sol is positively or negatively charged.

**Hint:** Recall that the dispersed phase can carry either a positive or negative charge, which classifies the sol accordingly.

### Step 2: Analyze Each Option
1. **Gold Sol**
- Gold sol consists of gold particles dispersed in a liquid.
- Gold sols are known to carry a negative charge.

**Conclusion:** Gold sol is a negatively charged sol.

2. **Persian Blue Dye**
- Persian blue dye consists of particles that are positively charged when dispersed in a liquid.

**Conclusion:** Persian blue dye is a positively charged sol.

3. **Hemoglobin**
- Hemoglobin is a protein that also carries a positive charge in its colloidal form.

**Conclusion:** Hemoglobin is a positively charged sol.

4. **Starch**
- Starch, when dispersed in a liquid, carries a negative charge.

**Conclusion:** Starch is a negatively charged sol.

### Step 3: Summarize the Findings
- From our analysis:
- Gold sol: Negatively charged
- Persian blue dye: Positively charged
- Hemoglobin: Positively charged
- Starch: Negatively charged

### Final Answer
The negatively charged sols from the options provided are:
- **Gold sol**
- **Starch**

### Summary
The correct options are **Gold sol** and **Starch**.