Which of the following is positively charged colloidal particle ?

Options

A. `As_(2)S_(3)`
B. `Al_(2)O_(3) . xH_(2)O`
C. Au
D. Pt

Answer

To determine which of the given options is a positively charged colloidal particle, we will analyze each option based on their behavior in an electric field during the process of electrophoresis.

### Step-by-Step Solution:

1. **Understanding Electrophoresis**:
- Electrophoresis is a process where charged particles move in an electric field. Positively charged particles move towards the negative electrode (cathode), while negatively charged particles move towards the positive electrode (anode).

2. **Analyzing Each Option**:
- **Option A: H2S3**:
- If H2S3 moves towards the positive pole, it indicates that it is negatively charged. Therefore, this option is not correct.

- **Option B: Al2O3.xH2O**:
- If Al2O3.xH2O moves towards the negative pole, it indicates that it is positively charged. This option could be correct.

- **Option C: Au (Gold)**:
- If Au moves towards the positive pole, it indicates that it is negatively charged. Therefore, this option is not correct.

- **Option D: Palladium**:
- If Palladium moves towards the positive pole, it indicates that it is also negatively charged. Therefore, this option is not correct.

3. **Conclusion**:
- Based on the analysis, the only option that is positively charged is **Option B: Al2O3.xH2O**.

### Final Answer:
- The positively charged colloidal particle is **B: Al2O3.xH2O**.