Question

The McCabe-Thiele method used to find the number of theoretical stages required in a distillation operation is based on the assumption(s) that:

• A. liquid/vapour loading in each section of the tower remains constant
• B. Trouton's rule is applicable
• C. sensible heat differences are small because the temperature change from tray to tray is small
• D. liquid mixture forms an azeotrope

Hint:

The McCabe-Thiele method is based on simplifying assumptions like constant liquid/vapour load, small sensible heat differences, and applicability of Trouton's rule.

Answer 1

The Correct Option is A, B, C

Step 1: Understand the McCabe-Thiele method.
The McCabe-Thiele method is used for determining the number of theoretical stages required in a distillation column. The assumptions behind the method are: - (A) **Liquid/vapour loading in each section of the tower remains constant**: This is one of the key assumptions in the McCabe-Thiele method, which assumes constant molar flow rates for the liquid and vapour. - (B) **Trouton's rule is applicable**: Trouton's rule is relevant for calculating the heat of vaporization and is typically used in distillation calculations. - (C) **Sensible heat differences are small because the temperature change from tray to tray is small**: This assumption is also part of the McCabe-Thiele method to simplify the temperature profile across the column. - (D) **Liquid mixture forms an azeotrope**: This is not a necessary assumption for the McCabe-Thiele method, as the method can be applied to systems that do not form azeotropes.

Final Answer: \[ \boxed{\text{A, B, C}} \]