Question

With reference to a two component system, a vapor line indicates ________

(a) A region where the temperature and pressure remains stable

(b) A region where the solubility remains constant

(c) An area below which components do not mingle

(d) An area above which both the components mingle to form a single mixture

I got this question in an online quiz.

I'd like to ask this question from Two Component System topic in portion Phase Rule of Engineering Chemistry I

Answer 1

Correct choice is (a) A region where the temperature and pressure remains stable

To elaborate: A vapor line is another name for an isotherm. It represents constant temperature and constant pressure relation at which the equilibrium is obtained. A  vapor line helps in finding out equilibrium concentrations.