Question

Colligative properties can be used to determine the molecular mass of solutes in solutions.

(a) What do you mean by ‘Colligative Property’?

(b) Fordeterminingthe molecular mass of polymers, osmotic pressure is preferred to other properties. Why?

(c) For intravenous injections only solutions with freezing point depression equal to that of 0.9% NaCI solution is used. Why?

Answer 1

(a) Colligative properties are those properties which depend upon no. of particles in the solution.

(b) 

(i) Pressure measurement can be done around the room temperature.

(ii) Molarity of the solution is used instead of molality.

(iii) Its magnitude is large compared to other colligative properties.

(iv) Polymers have poor solubility.

(c) This is because the osmotic pressure associated with the fulid inside the blood cell is equivalent to that of 0.9 (m/w) sodium chloride solution, i.e., blood is isotonic with this solution.