Question

Solutions A and B are separated by a semipermeable membrane. For each of the following pair, determine the direction of flow of water (A to B or B to A)

a. A: 2.5 % glucose solution. B: 4.0 % glucose solution

b. A: 2.0 M NaCl solution. B: 0.9 M NaCl solution

Answer 1

Answer:-

As we know that osmosis is that phenomenon in which spontaneous movement of solvent molecules from lower concentration to higher concentartion through semipermeable membrane takes place.

(a) -

Given:-

A: 2.5 % glucose solution. B: 4.0 % glucose solution

So we know that 2.5 % glucose solution means that 2.5 g glucose dissolved in 100 mL water and 4.0 % glucose solution means that 4.0 g glucose dissolved in 100 mL water.

So the concentartion of glucose would as follows:-

A: 2.5 % glucose solution < B: 4.0 % glucose solution

2.5 g glucose (A) < 4.0 g glucose (B)

therefore

Lower concentration of glucose solution = A: 2.5 % glucose solution

and

Higher concentration of glucose solution = B: 4.0 % glucose solution

So

Spontaneous movement of water molecules from lower concentration (A: 2.5 % glucose solution) to higher concentartion (B: 4.0 % glucose solution) through semipermeable membrane takes place.

A: 2.5 % glucose solution      B: 4.0 % glucose solution (i.e the answer)

or

Direction of flow of water A to B (i.e the answer)

(b) -

Given:-

A: 2.0 M NaCl solution. B: 0.9 M NaCl solution

So we know that 2.0 % NaCl solution means that 2.0 g NaCl dissolved in 100 mL water and 0.9 % NaCl solution means that 0.9 g NaCl dissolved in 100 mL water.

So the concentartion of glucose would as follows:-

A: 2.0 M NaCl solution   > B: 0.9 M NaCl solution

2.0 g NaCl (A) > 0.9 g NaCl (B)

therefore

Lower concentration of NaCl solution = B: 0.9 M NaCl solution

and

Higher concentration of NaCl solution = A: 2.0 M NaCl solution

Spontaneous movement of water molecules from lower concentration (B: 0.9 M NaCl solution) to higher concentartion (A: 2.0 M NaCl solution) through semipermeable membrane takes place.

B: 0.9 M NaCl solution      A: 2.0 M NaCl solution (i.e the answer)

or

Direction of flow of water B to A (i.e the answer)