GATE 2025 Chemical Engineering, Q54 · Distillation
The correct answer is 41 to 45.
Question
A binary AB liquid mixture containing 30 mol% A is subjected to differential (Rayleigh) distillation at atmospheric pressure in order to recover 60 mol% A in the distillate. Assuming a constant relative volatility the average composition of the collected distillate is ____ mol% A (rounded off to nearest integer).
Official answer: 41 to 45
Why
GATE 2025 official key: 41 to 45 mol% A. Applying the Rayleigh equation with the given recovery target and relative volatility yields an average distillate composition of mol% A.
Explanation cross-checked for consistency. Final answer matches the official IIT answer key.