Question

A selectively permeable membrane separates two solutions. Water is able to pass through this membrane; however, sucrose (a disaccharide) and glucose (a monosaccharide) cannot pass. The membrane separates a 0.2-molar sucrose solution from a 0.2-molar glucose solution. With time, how will the solutions change?a. Nothing happens because the two solutions are isotonic to one another.

b. Water enters the sucrose solution because the sucrose molecule is a disaccharide and thus larger than the monosaccharide glucose.
c. Water leaves the sucrose solution because the sucrose molecule is a disaccharide and thus larger than the monosaccharide glucose.
d. The sucrose solution is hypertonic and will gain water because the total mass of sucrose is greater than that of glucose.
e. After the sucrose dissociates to two monosaccharides, water will be osmostically drawn to that side of the membrane.

Answer 1

a. Nothing happens because the two solutions are isotonic to one another.

Step-by-step explanation:

Two solutions of the same molarity are separated from each other by a membrane that allows water molecules but not the glucose or sucrose to move across it. Movement of water across the selectively permeable membrane occurs only when two solutions have different concentrations of solutes. In that case, water moves from a hypotonic solution towards a hypertonic solution. Since both sucrose and glucose solutions have the same tonicity, there would not be any change in the solution.