Which of the following statements does not apply to reverse osmosis?

Options

A. It is used for water purification
B. In this technique, pressure greater than osmotic pressure is applied to the system
C. It is a passive process
D. It is an active process

Answer

To determine which statement does not apply to reverse osmosis, we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding Reverse Osmosis**:
- Reverse osmosis is a process used for water purification. It involves the movement of water through a semi-permeable membrane from a region of lower solute concentration to a region of higher solute concentration, but this process is driven by applying pressure greater than the osmotic pressure.

2. **Analyzing the Options**:
- **Option A**: "It is used for water purification."
- This statement is true. Reverse osmosis is commonly used in water purification systems to remove impurities and contaminants from water.

- **Option B**: "In this technique, pressure greater than osmotic pressure is applied to the system."
- This statement is also true. Reverse osmosis requires the application of pressure to overcome the osmotic pressure and facilitate the movement of water through the membrane.

- **Option C**: "It is a passive process."
- This statement is false. Reverse osmosis is not a passive process; it requires energy input to apply pressure to the system, making it an active process.

- **Option D**: "It is an active process."
- This statement is true. As mentioned, reverse osmosis requires energy to function, which categorizes it as an active process.

3. **Conclusion**:
- The statement that does not apply to reverse osmosis is **Option C**: "It is a passive process."

### Final Answer:
**Option C: It is a passive process.**

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