Which of the following chemical entities can act as semipermeable membrane ?

Options

A. `Cu_(2)[Fe(CN)_(6)]`
B. `Cu(SCN_(2)`
C. `BaC_(2)O_(4)`
D. `BaSO_(4)`

Answer

To determine which of the given chemical entities can act as a semipermeable membrane, we need to analyze the properties of each option in relation to the characteristics of a semipermeable membrane.

### Step-by-Step Solution:

1. **Understanding Semipermeable Membrane**:
A semipermeable membrane allows certain small particles (like water and ions) to pass through while blocking larger particles (like sugars and proteins).

2. **Analyzing the Options**:
- **Copper Ferrocyanate**: This compound forms a precipitate with small pores. These pores are capable of allowing small particles to pass through while blocking larger ones. Therefore, it can act as a semipermeable membrane.

- **Copper Thiocyanate**: This compound does not typically form a structure with the necessary pore size to selectively allow small particles to pass while blocking larger ones. Thus, it is not suitable as a semipermeable membrane.

- **Barium Oxalate**: Similar to copper thiocyanate, barium oxalate does not have the appropriate properties to function as a semipermeable membrane. It does not form a structure with selective permeability.

- **Barium Sulfate**: This compound is known for being insoluble in water and does not have the characteristics of a semipermeable membrane. It does not allow the passage of small particles effectively.

3. **Conclusion**:
Among the given options, **Copper Ferrocyanate** is the only chemical entity that can act as a semipermeable membrane due to its ability to form small pores that selectively allow the passage of small particles.

### Final Answer:
**Copper Ferrocyanate** can act as a semipermeable membrane.

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