Final answer:
The Na+Cl- solute cannot be fully recovered with any of the membranes due to their impermeability to electrically charged ions.
Step-by-step explanation:
The reason there is not 100% recovery of the Na+Cl- solute with any of the membranes is because membranes are impermeable to electrically charged ions like Na+ and Cl-. These ions cannot easily pass through the nonpolar lipid bilayer of the membrane without the help of membrane transport proteins. While membranes are freely permeable to water, they do not allow the passage of charged ions like Na+ and Cl-. Therefore, some of the solute is unable to pass through the membrane, resulting in less than 100% recovery.