Gibbs phase rule for general system is

Options

A. P+F=C-1
B. P+F=C+1
C. P+F=C-2
D. P+F=C+2

Answer

**Step-by-Step Solution:**

1. **Understanding Gibbs Phase Rule**: The Gibbs phase rule is a fundamental principle in thermodynamics that relates the number of phases in a system to the number of components and the degrees of freedom. It helps in understanding how many variables can be changed independently without affecting the others.

2. **Formula of Gibbs Phase Rule**: The Gibbs phase rule is mathematically expressed as:
\[ F = C - P + 2 \]
where:
- \( F \) = Degrees of freedom (the number of independent variables that can be changed)
- \( C \) = Number of components (chemically independent constituents)
- \( P \) = Number of phases (distinct physical forms of matter)

3. **Rearranging the Formula**: The formula can also be rearranged to show the relationship between the variables:
\[ P + F = C + 2 \]
This rearrangement emphasizes that the sum of the number of phases and degrees of freedom equals the number of components plus two.

4. **Conclusion**: Therefore, the Gibbs phase rule for a general system can be summarized as:
\[ F = C - P + 2 \]
or equivalently,
\[ P + F = C + 2 \]