Final Answer:
The osmolarity of the solution after the blood is added, with an impermeable membrane to NaCl and permeable to urea and water, will be 0.25 osmol/L.
Step-by-step explanation:
Osmolarity is a measure of the concentration of solute particles in a solution, expressed in osmoles per liter (osmol/L). In this scenario, the solution contains 0.15M NaCl and 0.1M urea. Since the membrane is impermeable to NaCl, it remains within the solution, contributing 0.15 osmol/L to the osmolarity.
Urea, being a covalent molecule, is permeable to the membrane and can freely pass through it. Therefore, the contribution of urea to the osmolarity after the blood is added is 0.1 osmol/L. The total osmolarity of the solution is the sum of these contributions, resulting in a final osmolarity of 0.25 osmol/L.
This calculation is based on the principle that impermeant solutes, such as NaCl in this case, do not move across a semipermeable membrane, while permeant solutes, like urea, can move freely. The movement of water across the membrane is driven by the osmotic pressure difference created by the impermeant solutes.
In this specific case, the osmolarity reflects the total solute concentration that influences the movement of water across the membrane. The osmolarity of the solution is a crucial factor in understanding the osmotic behavior and the movement of water in biological systems, particularly in situations where membranes have selective permeability to different solutes.