Question

What is the definition of a lower critical temperature?

(a) The minimum temperature at which equilibrium is achieved

(b) The lowest temperature at which two components will attain vapor state

(c) The lowest temperature at which two components sublimates

(d) The lowest temperature at which two components form a mixture

I had been asked this question in final exam.

My doubt is from Two Component System topic in chapter Phase Rule of Engineering Chemistry I

Answer 1

Correct answer is (a) The minimum temperature at which equilibrium is achieved

Easiest explanation: The lower critical solution temperature is the lowest temperature at which two components are insoluble and attains equilibrium. Conversely, the upper critical solution temperature is the highest temperature at which two components are soluble as single phase.