Question

Define osmotic pressure. Why is measurement of osmotic pressure method preferred for the determination of molar masses of macromolecules such as proteins and polymers?

Hint:

Osmotic pressure is a useful method for determining molar masses of substances that are too large to volatilize or are not easily distilled.

Answer 1

Osmotic pressure is the pressure exerted by a solution when it is separated from a pure solvent by a semipermeable membrane. It occurs due to the movement of solvent molecules from an area of lower solute concentration to an area of higher solute concentration. The measurement of osmotic pressure is preferred for determining the molar masses of macromolecules because it is a colligative property, which depends on the number of solute particles rather than their nature. This method is particularly useful for large molecules like proteins and polymers, which may not be easily analyzed by other methods.