(a) Define the so-called 'colligative' properties, and write brief notes about each of them.

(b) A system comprises two liquid components.  State whether the system would be likely to display positive deviation from ideality, approximate ideality, or negative deviation, if:

(i)  the Henry's law constants are larger than the Raoult constants for both components;

(ii) the Henry's law constants are approximately equal to the Raoult constants for both components;

For clarity, sketch the overall profile of total vapour pressure with system composition for answers (i) and (ii) above.

(c) An osmotic molecular-weight determination for a large polymer dissolved in benzene resulted in the following data:

Write down the van't Hoff equation applicable to this situation, and estimate the molar mass of the dissolved polymer.