X and Y represent two open compartments, X contains 1 liter of 4mM KCl in water and Compartment Y has 1 liter solution containing 2mM NaCl in water.
X and Y are separated by a semi-permeable membrane that is permeable to K+ ions and water but not to Na+ and Cl- ions. At equilibrium, which of the following statement(S) is (are) correct?
A) Compartment X will be negatively charged
B) Compartment X will have greater volume than Y
C) The concentration of Cl- is higher in X than Y
D) All of the above.
The answer is D, all of the above. I understand A and C are correct, but why is B correct?