Step 1: Define the degree of freedom.
In a two-component system, the degree of freedom \( F \) is given by the formula:
\[
F = C - P
\]
where \( C \) is the number of components and \( P \) is the number of phases. Since the system is two-component, \( C = 2 \). Thus, the formula becomes:
\[
F = 2 - P
\]
Step 2: Conclusion.
The degree of freedom for the system is \( F = 2 - P \), which corresponds to option (2).
For a single component system at vapor-liquid equilibrium, the extensive variables A, V, S and N denote the Helmholtz free energy, volume, entropy, and number of moles, respectively, in a given phase. If superscripts \( (\nu) \) and \( (\ell) \) denote the vapor and liquid phase, respectively, the relation that is NOT CORRECT is