Osmosis depends on

• A. The number of solute particles present
• B. The total volume of solution
• C. The polarity of the solute
• D. The charge of the solute

Answer: (A)

Osmosis is driven by the concentration difference of dissolved particles across a semipermeable membrane. The force pushing water to move is osmotic pressure, which increases with the number of solute particles present in the solution. In other words, more dissolved particles means a stronger pull for water to balance concentrations, and for electrolytes, dissociation adds more particles, boosting osmotic pressure even further. The total volume of the solution isn’t the deciding factor by itself—it's the concentration (how many solute particles per unit volume) that matters. The polarity or charge of the solute doesn’t directly drive water movement across the membrane; osmotic flow depends on the solute concentration gradient, not on the specific chemical properties of the solute.