Question

A semipermeable membrane separates two aqueous solutions at 37 °C. For each of the following cases, name the solution into which a net flow of water (if any) will occur.

Net flow is toward solution a; Net flow is toward solution B; no net flow

choices to be labeled under the 3 categories above:

- Solution A= 0.10M NaCl (aq) Solution B=0.01 M NaCl (aq)

-Solution A=0.20 M KCl (aq) Solution B= 0.20 M NaCl (aq)

-Solution A= 0.10 M NaHCO3 (aq) Solution B= 0.20 M NaHCO3 (aq)

Answer 1

First calculate the total number of ions in Solution A and Solution B as follows:
For the first set:

Solution A= 0.10M NaCl (aq)

0.10 M *( 1 mole Na + 1 mol Cl-) =0.2 mol        

Solution B=0.01 M NaCl (aq)

0.10 M *( 1 mole Na + 1 mol Cl-) =0.02 mol      

In this set lower molarity will flow into the higher.

For the second set:

Solution A=0.20 M KCl (aq)

0.20 M *( 1 mole K + 1 mol Cl-) =0.4 mol          

Solution B= 0.20 M NaCl (aq)

0.20 M *( 1 mole Na + 1 mol Cl-) =0.4 mol        

In this set there will not flow due to same number of molarity.

For the third set:

Solution A= 0.10 M NaHCO3 (aq)

0.10 M *( 1 mole Na + 1 mol H++ 1 mol CO32-) =0.3 mol   

Solution B= 0.20 M NaHCO3 (aq)

0.20 M *( 1 mole Na + 1 mol H++ 1 mol CO32-) =0.6 mol

In this set lower molarity will flow into the higher.