Concept explainers
Plants that thrive in salt water must have internal solutions (inside the plant cells) that are isotonic (same osmotic pressure) with the surrounding solution. A leaf of a saltwater plant is able to thrive in an aqueous salt solution (at 25°C) that has a freezing point equal to 20.621°C. You would like to use this information to calculate the osmotic pressure of the solution in the cell.
a. In order to use the freezing-point depression to calculate osmotic pressure, what assumption must you
make (in addition to ideal behavior of the solutions, which we will assume)?
b. Under what conditions is the assumption in part a reasonable?
c. Solve for the osmotic pressure (at 25°C) of the solution in the plant cell.
d. The plant leaf is placed in an aqueous salt solution (at 25°C) that has a boiling point of 102.0°C. What will happen to the plant cells in the leaf?
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