Solution A has `Psi_(s)` =-30 bars and `Psi_(p)` = 5 bars. Solution B has `Psi_(s)` = -10 bars and `Psi_(p)` = 0 atm. The two are separated by semipermeable membrane . Flow of water will be
(a) B to A
(b) A to B
(c) Equal in both directions
(d) No flow of water

Options

A. B to A
B. A to B
C. Equal in both directions
D. No flow of water .

Answer

To determine the flow of water between Solution A and Solution B, we need to calculate the water potential (Ψ) for each solution using the formula:

\[ \Psi = \Psi_s + \Psi_p \]

Where:
- Ψ is the water potential
- Ψ_s is the solute potential
- Ψ_p is the pressure potential

### Step 1: Calculate the Water Potential of Solution A
Given:
- Ψ_s (A) = -30 bars
- Ψ_p (A) = 5 bars

Using the formula:
\[ \Psi (A) = \Psi_s (A) + \Psi_p (A) \]
\[ \Psi (A) = -30 + 5 \]
\[ \Psi (A) = -25 \text{ bars} \]

### Step 2: Calculate the Water Potential of Solution B
Given:
- Ψ_s (B) = -10 bars
- Ψ_p (B) = 0 bars

Using the formula:
\[ \Psi (B) = \Psi_s (B) + \Psi_p (B) \]
\[ \Psi (B) = -10 + 0 \]
\[ \Psi (B) = -10 \text{ bars} \]

### Step 3: Compare the Water Potentials
Now we compare the water potentials of both solutions:
- Ψ (A) = -25 bars
- Ψ (B) = -10 bars

### Step 4: Determine the Direction of Water Flow
Water moves from an area of higher water potential to an area of lower water potential. Since -10 bars (Solution B) is greater than -25 bars (Solution A), water will flow from Solution B to Solution A.

### Conclusion
The flow of water will be from Solution B to Solution A. Therefore, the correct answer is:
**(a) B to A**

---