Question

Which of the following condition is correct for reverse osmosis?

• A. \( P_{\text{ext}} = CRT \)
• B. \( P_{\text{ext}}>CRT \)
• C. \( P_{\text{ext}}<CRT \)
• D. \( P_{\text{ext}} = nRT \)

Hint:

Reverse osmosis requires pressure greater than osmotic pressure: \( P_{\text{ext}}>CRT \)

Answer 1

The Correct Option is B

- Osmotic pressure \( \pi = CRT \)
- In reverse osmosis, external pressure \( P_{\text{ext}} \) is applied to reverse the natural flow.
\[ \text{For reverse osmosis to occur: } P_{\text{ext}}>\pi = CRT \] This forces pure solvent to move from solution to the other side of the semipermeable membrane.