Question

Feed solution F is contacted with solvent B in an extraction process. Carrier liquid in the feed is A and the solute is C. The ternary diagram depicting a single ideal stage extraction is given below. The dashed lines represent the tie-lines.

The CORRECT option(s) is/are

• A. For the tie-lines shown, concentration of solute in the extract is higher than that in the raffinate
• B. Maximum amount of solvent is required if the mixture composition is at W
• C. Y represents the composition of extract when minimum amount of solvent is used
• D. U represents the raffinate composition if the mixture composition is at M

Hint:

On ternary diagrams: Extract lies toward solvent apex; raffinate lies toward carrier liquid apex; tie-lines connect corresponding phase compositions.

Answer 1

The Correct Option is A, C, D

(A) True: Along a tie-line, the extract phase (closer to solvent-rich B–C region) always has higher solute content than the raffinate.
[4pt] (B) False: Point W lies near the middle of the binodal curve; it does not require the maximum solvent. Point P (far right) generally demands more solvent.
[4pt] (C) True: Y lies on a tie-line corresponding to minimum solvent usage because it is closer to the feed line, minimizing phase separation shift.
[4pt] (D) True: When the feed composition is at M, the raffinate composition corresponds to U on the same tie-line.