In a beaker a compartment a has 25% glucose solution and compartment b has 5% glu glucose solution. the membrane is permeable to the solvent but not to the solute. what transport mechanism causes water to move from a to

Answer is: osmotic pressure.

The direction of osmotic pressure is always from the side with the lower concentration of solute to the side with the higher concentration, in this example, from solution b (5% glucose) to solution b (25% glucose).

Osmotic pressure, alongside the vapor pressure depression, freezing point depression and the boiling point elevation are the colligative properties od solution.