According to the rules of osmosis, at what point will a system reach a state of equilibrium?
A system will reach equilibrium when the ______ (Answer) on both sides of a water-permeable membrane are equal.
Answers:
a) concentration of solute molecules
b) number of solute molecules
c) number of solvent molecules
d) volume of water
The Correct Answer and Explanation is :
The correct answer is:
a) concentration of solute molecules.
Explanation:
Osmosis is the movement of water molecules through a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. This process continues until equilibrium is reached, where the concentration of solute molecules is equal on both sides of the membrane.
At equilibrium, water movement still occurs across the membrane, but there is no net movement in one direction or the other. This means that the system has reached a state where the concentration of solute molecules on both sides of the membrane is balanced. The driving force behind osmosis is the difference in solute concentration, known as the concentration gradient. Water naturally moves toward the side with a higher solute concentration to dilute it, attempting to equalize solute concentrations across the membrane.
Why not other options?
- b) Number of solute molecules: The number of solute molecules on each side does not need to be equal; what matters is their concentration. If one side has more solvent (water), it may also have a greater number of solute molecules, but the concentration might still be equal.
- c) Number of solvent molecules: The equilibrium in osmosis is based on the solute concentration, not the solvent concentration. The volume of water on either side can be unequal, but the movement of water will continue until the concentration of solutes is balanced.
- d) Volume of water: The volume of water on both sides of the membrane may be different, as water will move to dilute the side with more solute. The equilibrium is not determined by equal volumes but by equal solute concentrations.
Thus, equilibrium in osmosis is primarily driven by solute concentration, making option a correct.