Explanation:

The formula for the condensed phase rule is given by option B: F = C - P.

Here's the breakdown of the formula and what each variable represents:

- F: The degrees of freedom, which represents the number of variables that can be varied independently without affecting the number of phases in the system.

- C: The number of components in the system. A component is a chemically independent and distinguishable species that makes up the system. For example, in a mixture of water and ethanol, the two components are water and ethanol.

- P: The number of phases in the system. A phase is a physically distinct and homogeneous part of a system. It can be solid, liquid, or gas. For example, in a system with water and ethanol, if both are present as liquids, there is one liquid phase. But if one of them evaporates and forms a gas phase, there are two phases (liquid and gas).

The condensed phase rule is used to determine the number of variables (degrees of freedom) that can be independently varied in a system while keeping the number of phases constant.

By subtracting the number of phases (P) from the number of components (C), we can determine the degrees of freedom (F). The degrees of freedom represent the number of variables that can be freely adjusted without changing the number of phases in the system.

For example, if we have a system with two components (C = 2) and one phase (P = 1), the formula would be F = 2 - 1 = 1. This means that we have one degree of freedom, and we can vary one variable (such as temperature or pressure) while keeping the system as a single phase.

In summary, the condensed phase rule formula, F = C - P, allows us to determine the degrees of freedom in a system based on the number of components and phases present.