Question

What is critical solution temperature? Describe liquid pairs which have
(i) upper CST,
(ii) lower CST, and
(ii) both upper and lower CST.

Answer 1

Critical solution temperature is the temperature at which completemiscibility is reached.
(i) Above the upper CST two liquids are miscible in all proportions.
(ii) Below the lower CST two liquids are miscible in all compositions.
(iii) In the case of both upper andlower CST we expect partial miscibility.