What is the osmotic pressure of the salt solution in reverse-osmosis?
Select one:
a. An equilibrium state where the amount of solvent passing in opposite directions is equal
b. An equilibrium state where the amount of solvent passing in one direction is greater than other direction
c. The pressure of one side of the reverse-osmosis system is greater than the other side
d. When the pressure allows the salt solutes to pass through the semipermeable membrane
e. The pressure is increased above the osmosic presure to reverse the flow of the water from salt solution to the fresh solvent
I know the answer is either c, d or e, but not sure which is the right one. Hope someone can help. Thanks.
The correct answer is e. The osmotic pressure in reverse osmosis is increased above the osmotic pressure to reverse the flow of water from the salt solution to the fresh solvent. In reverse osmosis, pressure is applied to the salt solution to overcome the osmotic pressure and force water molecules to move from the concentrated salt solution to the fresh solvent through a semipermeable membrane.
To determine the correct answer, let's break down the concept of reverse osmosis and osmotic pressure:
Reverse osmosis is a process used to separate solvents from solutes by applying pressure to the solution and forcing it through a semipermeable membrane. The membrane allows the solvent (in this case, water) to pass through while preventing larger solute particles (such as salt) from crossing over.
Osmotic pressure, on the other hand, is the pressure required to prevent the flow of solvent particles (such as water) through a semipermeable membrane, driven by the concentration difference between the two sides of the membrane.
Given this background, let's analyze the options:
a. An equilibrium state where the amount of solvent passing in opposite directions is equal - This option doesn't directly address osmotic pressure in reverse osmosis.
b. An equilibrium state where the amount of solvent passing in one direction is greater than the other direction - This option seems plausible, as it hints at the flow of solvent through the membrane being unidirectional. However, it does not explicitly mention osmotic pressure.
c. The pressure of one side of the reverse-osmosis system is greater than the other side - This option captures the concept of pressure being imbalanced between the two sides, which can play a role in reverse osmosis. It could potentially be the correct answer.
d. When the pressure allows the salt solutes to pass through the semipermeable membrane - This option focuses on the ability of pressure to enable the passage of salt solutes, which is not in line with the purpose of reverse osmosis. In reverse osmosis, the pressure is applied to the solvent to push it through the membrane, while the solutes (like salt) are left behind.
e. The pressure is increased above the osmotic pressure to reverse the flow of water from salt solution to the fresh solvent - This option mentions increasing pressure above osmotic pressure to reverse the flow, which aligns with the principle of reverse osmosis. It could also be a potential correct answer.
Considering these explanations, the most accurate answer for the osmotic pressure of the salt solution in reverse osmosis would be either option c or option e. The correct choice depends on more specific details about the system or context given in the question or material you are studying.