Question

A closed system consists of a solution of liquid water and ethanol in equilibrium with its vapours. Using the Gibbs phase rule, the degree of freedom of the system is:

• A. 0
• B. 1
• C. 2
• D. 3

Hint:

The Gibbs phase rule helps in determining the number of independent variables (such as pressure, temperature) that can be specified in a system at equilibrium.

Answer 1

The Correct Option is C

The Gibbs phase rule is used to determine the degree of freedom in a system. The formula for the degree of freedom (\( F \)) is given by: \[ F = C - P + 2, \] where \( C \) is the number of components and \( P \) is the number of phases. In this case:
- The system consists of two components: liquid water and ethanol.
- The system is in equilibrium with its vapours, meaning there are two phases (liquid and vapour).
Thus, the degree of freedom is: \[ F = 2 - 2 + 2 = 2. \] Hence, the correct answer is \( (C) 2 \). Final Answer: (C) 2