Which of the following is/are state function?

Options

A. Enthalpy
B. Heat
C. Entropy
D. Gibb's free energy(G)

Answer

To determine which of the given options are state functions, we need to understand the definition of state functions and path functions.

### Step-by-Step Solution:

1. **Define State Functions**:
State functions are properties of a system that depend only on the current state of the system, not on the path taken to reach that state. Examples include internal energy, enthalpy, entropy, and Gibbs free energy.

2. **Analyze Each Option**:
- **Enthalpy (H)**: Enthalpy is a state function because its value depends only on the current state of the system (temperature, pressure, and composition) and not on how the system reached that state.
- **Heat (q)**: Heat is a path function because it depends on the specific process or path taken to transfer energy into or out of the system.
- **Entropy (S)**: Entropy is a state function as it depends only on the state of the system and not on the process used to change that state.
- **Gibbs Free Energy (G)**: Gibbs free energy is also a state function because it is determined by the state variables of the system (temperature, pressure, and composition).

3. **Conclusion**:
Among the given options:
- Enthalpy (H) - State Function
- Heat (q) - Not a State Function (Path Function)
- Entropy (S) - State Function
- Gibbs Free Energy (G) - State Function

Thus, the state functions from the options provided are Enthalpy, Entropy, and Gibbs Free Energy.

### Final Answer:
The state functions are Enthalpy, Entropy, and Gibbs Free Energy.